chore(deps): update peter-evans/create-pull-request digest to 9ec683e

fix(er-diagram): handle syntax errors for special characters in node names

.changeset/deep-pumas-run.md

@@ -0,0 +1,5 @@
+---
+'mermaid': patch
+---
+
+chore: Fix mindmap rendering in docs and apply tidytree layout

.changeset/four-eyes-wish.md

@@ -0,0 +1,5 @@
+---
+'mermaid': patch
+---
+
+fix: Ensure edge label color is applied when using classDef with edge IDs

.changeset/loud-results-melt.md

@@ -0,0 +1,5 @@
+---
+'mermaid': minor
+---
+
+feat: Add half-arrowheads (solid & stick) and central connection support

.changeset/moody-fans-try.md

@@ -0,0 +1,5 @@
+---
+'mermaid': patch
+---
+
+fix: Resolve gantt chart crash due to invalid array length

.changeset/proud-colts-smell.md

@@ -0,0 +1,5 @@
+---
+'mermaid': minor
+---
+
+feat: Add IDs in architecture diagrams

.changeset/revert-marked-dependency.md

@@ -0,0 +1,9 @@
+---
+'mermaid': patch
+---
+
+chore: revert marked dependency from ^15.0.7 to ^16.0.0
+
+- Reverted marked package version to ^16.0.0 for better compatibility
+- This is a dependency update that maintains API compatibility
+- All tests pass with the updated version

.changeset/sweet-games-build.md

@@ -0,0 +1,5 @@
+---
+'mermaid': patch
+---
+
+fix(er-diagram): prevent syntax error when using 'u', numbers, and decimals in node names

.github/workflows/codeql.yml

@@ -26,8 +26,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        language: ['javascript']
-        # CodeQL supports [ 'cpp', 'csharp', 'go', 'java', 'javascript', 'python', 'ruby' ]
+        language: ['javascript', 'actions']
+        # CodeQL supports [ 'actions', 'cpp', 'csharp', 'go', 'java', 'javascript', 'python', 'ruby' ]
         # Learn more about CodeQL language support at https://aka.ms/codeql-docs/language-support
 
     steps:

.github/workflows/e2e-timings.yml

@@ -58,7 +58,7 @@ jobs:
           echo "EOF" >> $GITHUB_OUTPUT
 
       - name: Commit and create pull request
-        uses: peter-evans/create-pull-request@915d841dae6a4f191bb78faf61a257411d7be4d2
+        uses: peter-evans/create-pull-request@9ec683ee07f9121fdf529b923931dd78d977a5c9
         with:
           add-paths: |
             cypress/timings.json

cypress/integration/rendering/erDiagram.spec.js

@@ -369,4 +369,92 @@ ORDER ||--|{ LINE-ITEM : contains
       );
     });
   });
+
+  describe('Special characters and numbers syntax', () => {
+    it('should render ER diagram with numeric entity names', () => {
+      imgSnapshotTest(
+        `
+        erDiagram
+          1 ||--|| ORDER : places
+          ORDER ||--|{ 2 : contains
+          2 ||--o{ 3.5 : references
+        `,
+        { logLevel: 1 }
+      );
+    });
+
+    it('should render ER diagram with "u" character in entity names and cardinality', () => {
+      imgSnapshotTest(
+        `
+        erDiagram
+          CUSTOMER ||--|| u : has
+          u ||--|| ORDER : places
+          PROJECT u--o{ TEAM_MEMBER : "parent"
+        `,
+        { logLevel: 1 }
+      );
+    });
+
+    it('should render ER diagram with decimal numbers in relationships', () => {
+      imgSnapshotTest(
+        `
+        erDiagram
+          2.5 ||--|| 1.5 : has
+          CUSTOMER ||--o{ 3.14 : references
+          1.0 ||--|{ ORDER : contains
+        `,
+        { logLevel: 1 }
+      );
+    });
+
+    it('should render ER diagram with numeric entity names and attributes', () => {
+      imgSnapshotTest(
+        `
+        erDiagram
+          1 {
+            string name
+            int value
+          }
+          1 ||--|| ORDER : places
+          ORDER {
+            float price
+            string description
+          }
+        `,
+        { logLevel: 1 }
+      );
+    });
+
+    it('should render complex ER diagram with mixed special entity names', () => {
+      imgSnapshotTest(
+        `
+        erDiagram
+          CUSTOMER ||--o{ 1 : places
+          1 ||--|{ u : contains
+          1.5
+          u ||--|| 2.5 : processes
+          2.5 {
+            string id
+            float value
+          }
+          u {
+            varchar(50) name
+            int count
+          }
+        `,
+        { logLevel: 1 }
+      );
+    });
+    it('should render ER diagram with numeric entity names and attributes', () => {
+      imgSnapshotTest(
+        `erDiagram
+         PRODUCT ||--o{ ORDER-ITEM : has
+         1.5
+         u
+         1
+        `,
+        { logLevel: 1 }
+      );
+    });
+  });
 });

cypress/integration/rendering/sequencediagram-v2.spec.js

@@ -655,5 +655,126 @@ describe('Sequence Diagram Special Cases', () => {
         expect(svg).to.not.have.attr('style');
       });
     });
+
+    describe('Central Connection Rendering Tests', () => {
+      it('should render central connection circles on actor vertical lines', () => {
+        imgSnapshotTest(
+          `sequenceDiagram
+        participant Alice
+        participant Bob
+        participant Charlie
+        Alice ()->>() Bob: Central connection
+        Bob ()-->> Charlie: Reverse central connection
+        Charlie ()<<-->>() Alice: Dual central connection`,
+          { look: 'classic', sequence: { diagramMarginX: 50, diagramMarginY: 10 } }
+        );
+      });
+
+      it('should render central connections with different arrow types', () => {
+        imgSnapshotTest(
+          `sequenceDiagram
+        participant Alice
+        participant Bob
+        Alice ()->>() Bob: Solid open arrow
+        Alice ()-->>() Bob: Dotted open arrow
+        Alice ()-x() Bob: Solid cross
+        Alice ()--x() Bob: Dotted cross
+        Alice ()->() Bob: Solid arrow`,
+          { look: 'classic', sequence: { diagramMarginX: 50, diagramMarginY: 10 } }
+        );
+      });
+
+      it('should render central connections with bidirectional arrows', () => {
+        imgSnapshotTest(
+          `sequenceDiagram
+        participant Alice
+        participant Bob
+        Alice ()<<->>() Bob: Bidirectional solid
+        Alice ()<<-->>() Bob: Bidirectional dotted`,
+          { look: 'classic', sequence: { diagramMarginX: 50, diagramMarginY: 10 } }
+        );
+      });
+
+      it('should render central connections with activations', () => {
+        imgSnapshotTest(
+          `sequenceDiagram
+        participant Alice
+        participant Bob
+        participant Charlie
+        Alice ()->>() Bob: Activate Bob
+        activate Bob
+        Bob ()-->> Charlie: Message to Charlie
+        Bob ()->>() Alice: Response to Alice
+        deactivate Bob`,
+          { look: 'classic', sequence: { diagramMarginX: 50, diagramMarginY: 10 } }
+        );
+      });
+
+      it('should render central connections mixed with normal messages', () => {
+        imgSnapshotTest(
+          `sequenceDiagram
+        participant Alice
+        participant Bob
+        participant Charlie
+        Alice ->> Bob: Normal message
+        Bob ()->>() Charlie: Central connection
+        Charlie -->> Alice: Normal dotted message
+        Alice ()<<-->>() Bob: Dual central connection
+        Bob -x Charlie: Normal cross message`,
+          { look: 'classic', sequence: { diagramMarginX: 50, diagramMarginY: 10 } }
+        );
+      });
+
+      it('should render central connections with notes', () => {
+        imgSnapshotTest(
+          `sequenceDiagram
+        participant Alice
+        participant Bob
+        participant Charlie
+        Alice ()->>() Bob: Central connection
+        Note over Alice,Bob: Central connection note
+        Bob ()-->> Charlie: Reverse central connection
+        Note right of Charlie: Response note
+        Charlie ()<<-->>() Alice: Dual central connection`,
+          { look: 'classic', sequence: { diagramMarginX: 50, diagramMarginY: 10 } }
+        );
+      });
+
+      it('should render central connections with loops and alternatives', () => {
+        imgSnapshotTest(
+          `sequenceDiagram
+        participant Alice
+        participant Bob
+        participant Charlie
+        loop Every minute
+            Alice ()->>() Bob: Central heartbeat
+            Bob ()-->> Charlie: Forward heartbeat
+        end
+        alt Success
+            Charlie ()<<-->>() Alice: Success response
+        else Failure
+            Charlie ()-x() Alice: Failure response
+        end`,
+          { look: 'classic', sequence: { diagramMarginX: 50, diagramMarginY: 10 } }
+        );
+      });
+
+      it('should render central connections with different participant types', () => {
+        imgSnapshotTest(
+          `sequenceDiagram
+          participant Alice
+          actor Bob
+          participant Charlie@{"type":"boundary"}
+          participant David@{"type":"control"}
+          participant Eve@{"type":"entity"}
+          Alice ()->>() Bob: To actor
+          Bob ()-->> Charlie: To boundary
+          Charlie ()->>() David: To control
+          David ()<<-->>() Eve: To entity
+          Eve ()-x() Alice: Back to participant`,
+          { look: 'classic', sequence: { diagramMarginX: 50, diagramMarginY: 10 } }
+        );
+      });
+    });
   });
 });

cypress/integration/rendering/sequencediagram.spec.js

@@ -1053,4 +1053,167 @@ describe('Sequence diagram', () => {
       ]);
     });
   });
+  describe('render new arrow type', () => {
+    it('should render Solid half arrow top', () => {
+      imgSnapshotTest(
+        `
+    sequenceDiagram
+      Alice -|\\  John: Hello John, how are you? 
+      Alice-|\\  John: Hi Alice, I can hear you!
+      Alice -|\\  John: Test
+      `
+      );
+    });
+    it('should render Solid half arrow bottom', () => {
+      imgSnapshotTest(
+        `
+    sequenceDiagram
+      Alice-|/John: Hello John, how are you?
+      Alice-|/John: Hi Alice, I can hear you!
+      Alice-|/John: Test
+      `
+      );
+    });
+
+    it('should render Stick half arrow top ', () => {
+      imgSnapshotTest(
+        `
+     sequenceDiagram
+      Alice-\\\\John: Hello John, how are you?
+      Alice-\\\\John: Hi Alice, I can hear you!
+      Alice-\\\\John: Test
+      `
+      );
+    });
+    it('should render Stick half arrow bottom ', () => {
+      imgSnapshotTest(
+        `
+       sequenceDiagram
+      Alice-//John: Hello John, how are you?
+      Alice-//John: Hi Alice, I can hear you!
+      Alice-//John: Test
+      `
+      );
+    });
+    it('should render Solid half arrow top reverse ', () => {
+      imgSnapshotTest(
+        `
+       sequenceDiagram
+      Alice/|-John: Hello Alice, how are you?
+      Alice/|-John: Hi Alice, I can hear you!
+      Alice/|-John: Test
+
+      `
+      );
+    });
+
+    it('should render Solid half arrow bottom reverse ', () => {
+      imgSnapshotTest(
+        `sequenceDiagram
+        Alice \\|- John: Hello Alice, how are you?
+        Alice \\|- John: Hi Alice, I can hear you!
+        Alice \\|- John: Test`
+      );
+    });
+
+    it('should render Stick half arrow top reverse ', () => {
+      imgSnapshotTest(
+        `
+      sequenceDiagram
+      Alice //-John: Hello Alice, how are you?
+      Alice //-John: Hi Alice, I can hear you!
+      Alice //-John: Test`
+      );
+    });
+
+    it('should render Stick half arrow bottom reverse ', () => {
+      imgSnapshotTest(
+        `
+       sequenceDiagram
+      Alice \\\\-John: Hello Alice, how are you?
+      Alice \\\\-John: Hi Alice, I can hear you!
+      Alice \\\\-John: Test`
+      );
+    });
+
+    it('should render Solid half arrow top dotted', () => {
+      imgSnapshotTest(
+        `
+     sequenceDiagram
+      Alice --|\\John: Hello John, how are you?
+      Alice --|\\John: Hi Alice, I can hear you!
+      Alice --|\\John: Test`
+      );
+    });
+
+    it('should render Solid half arrow bottom dotted', () => {
+      imgSnapshotTest(
+        `
+     sequenceDiagram
+      Alice --|/John: Hello John, how are you?
+      Alice --|/John: Hi Alice, I can hear you!
+      Alice --|/John: Test`
+      );
+    });
+
+    it('should render Stick half arrow top dotted', () => {
+      imgSnapshotTest(
+        `
+     sequenceDiagram
+      Alice--\\\\John: Hello John, how are you?
+      Alice--\\\\John: Hi Alice, I can hear you!
+      Alice--\\\\John: Test`
+      );
+    });
+
+    it('should render Stick half arrow bottom dotted', () => {
+      imgSnapshotTest(
+        `
+     sequenceDiagram
+      Alice--//John: Hello John, how are you?
+      Alice--//John: Hi Alice, I can hear you!
+      Alice--//John: Test`
+      );
+    });
+
+    it('should render Solid half arrow top reverse dotted', () => {
+      imgSnapshotTest(
+        `
+  sequenceDiagram
+      Alice/|--John: Hello Alice, how are you?
+      Alice/|--John: Hi Alice, I can hear you!
+      Alice/|--John: Test`
+      );
+    });
+
+    it('should render Solid half arrow bottom reverse dotted', () => {
+      imgSnapshotTest(
+        `
+  sequenceDiagram
+      Alice\\|--John: Hello Alice, how are you?
+      Alice\\|--John: Hi Alice, I can hear you!
+      Alice\\|--John: Test`
+      );
+    });
+
+    it('should render Stick half arrow top reverse dotted ', () => {
+      imgSnapshotTest(
+        `
+  sequenceDiagram
+      Alice//--John: Hello Alice, how are you?
+      Alice//--John: Hi Alice, I can hear you!
+      Alice//--John: Test`
+      );
+    });
+
+    it('should render Stick half arrow bottom reverse dotted ', () => {
+      imgSnapshotTest(
+        `
+  sequenceDiagram
+      Alice\\\\--John: Hello Alice, how are you?
+      Alice\\\\--John: Hi Alice, I can hear you!
+      Alice\\\\--John: Test`
+      );
+    });
+  });
 });

docs/syntax/sequenceDiagram.md

@@ -329,7 +329,11 @@ Messages can be of two displayed either solid or with a dotted line.
 [Actor][Arrow][Actor]:Message text
 ```
 
-There are ten types of arrows currently supported:
+Lines can be solid or dotted, and can end with various types of arrowheads, crosses, or open arrows.
+
+#### Supported Arrow Types
+
+**Standard Arrow Types**
 
 | Type     | Description                                          |
 | -------- | ---------------------------------------------------- |
@@ -344,6 +348,58 @@ There are ten types of arrows currently supported:
 | `-)`     | Solid line with an open arrow at the end (async)     |
 | `--)`    | Dotted line with a open arrow at the end (async)     |
 
+**Half-Arrows (v\<MERMAID_RELEASE_VERSION>+)**
+
+The following half-arrow types are supported for more expressive sequence diagrams. Both solid and dotted variants are available by increasing the number of dashes (`-` → `--`).
+
+---
+
+| Type    | Description                                          |
+| ------- | ---------------------------------------------------- |
+| `-\|\`  | Solid line with top half arrowhead                   |
+| `--\|\` | Dotted line with top half arrowhead                  |
+| `-\|/`  | Solid line with bottom half arrowhead                |
+| `--\|/` | Dotted line with bottom half arrowhead               |
+| `/\|-`  | Solid line with reverse top half arrowhead           |
+| `/\|--` | Dotted line with reverse top half arrowhead          |
+| `\\-`   | Solid line with reverse bottom half arrowhead        |
+| `\\--`  | Dotted line with reverse bottom half arrowhead       |
+| `-\\`   | Solid line with top stick half arrowhead             |
+| `--\\`  | Dotted line with top stick half arrowhead            |
+| `-//`   | Solid line with bottom stick half arrowhead          |
+| `--//`  | Dotted line with bottom stick half arrowhead         |
+| `//-`   | Solid line with reverse top stick half arrowhead     |
+| `//--`  | Dotted line with reverse top stick half arrowhead    |
+| `\\-`   | Solid line with reverse bottom stick half arrowhead  |
+| `\\--`  | Dotted line with reverse bottom stick half arrowhead |
+
+## Central Connections (v\<MERMAID_RELEASE_VERSION>+)
+
+Mermaid sequence diagrams support **central lifeline connections** using a `()`.
+This is useful to represent messages or signals that connect to a central point, rather than from one actor directly to another.
+
+To indicate a central connection, append `()` to the arrow syntax.
+
+#### Basic Syntax
+
+```mermaid-example
+sequenceDiagram
+    participant Alice
+    participant John
+    Alice->>()John: Hello John
+    Alice()->>John: How are you?
+    John()->>()Alice: Great!
+```
+
+```mermaid
+sequenceDiagram
+    participant Alice
+    participant John
+    Alice->>()John: Hello John
+    Alice()->>John: How are you?
+    John()->>()Alice: Great!
+```
+
 ## Activations
 
 It is possible to activate and deactivate an actor. (de)activation can be dedicated declarations:

package.json

@@ -63,12 +63,12 @@
     ]
   },
   "devDependencies": {
-    "@applitools/eyes-cypress": "^3.44.9",
+    "@applitools/eyes-cypress": "^3.55.2",
     "@argos-ci/cypress": "^6.1.1",
     "@changesets/changelog-github": "^0.5.1",
-    "@changesets/cli": "^2.27.12",
+    "@changesets/cli": "^2.29.7",
     "@cspell/eslint-plugin": "^8.19.4",
-    "@cypress/code-coverage": "^3.12.49",
+    "@cypress/code-coverage": "^3.14.6",
     "@eslint/js": "^9.26.0",
     "@rollup/plugin-typescript": "^12.1.4",
     "@types/cors": "^2.8.19",
@@ -77,22 +77,22 @@
     "@types/jsdom": "^21.1.7",
     "@types/lodash": "^4.17.20",
     "@types/mdast": "^4.0.4",
-    "@types/node": "^22.13.17",
+    "@types/node": "^22.18.6",
     "@types/rollup-plugin-visualizer": "^5.0.3",
-    "@vitest/coverage-v8": "^3.0.9",
-    "@vitest/spy": "^3.0.9",
-    "@vitest/ui": "^3.0.9",
+    "@vitest/coverage-v8": "^3.2.4",
+    "@vitest/spy": "^3.2.4",
+    "@vitest/ui": "^3.2.4",
     "ajv": "^8.17.1",
     "chokidar": "3.6.0",
-    "concurrently": "^9.1.2",
+    "concurrently": "^9.2.1",
     "cors": "^2.8.5",
     "cpy-cli": "^5.0.0",
     "cross-env": "^7.0.3",
-    "cspell": "^9.1.5",
+    "cspell": "^9.2.1",
     "cypress": "^14.5.4",
     "cypress-image-snapshot": "^4.0.1",
-    "cypress-split": "^1.24.21",
-    "esbuild": "^0.25.9",
+    "cypress-split": "^1.24.23",
+    "esbuild": "^0.25.10",
     "eslint": "^9.26.0",
     "eslint-config-prettier": "^10.1.8",
     "eslint-plugin-cypress": "^4.3.0",
@@ -106,10 +106,10 @@
     "eslint-plugin-tsdoc": "^0.4.0",
     "eslint-plugin-unicorn": "^59.0.1",
     "express": "^5.1.0",
-    "globals": "^16.0.0",
+    "globals": "^16.4.0",
     "globby": "^14.1.0",
     "husky": "^9.1.7",
-    "jest": "^30.0.5",
+    "jest": "^30.1.3",
     "jison": "^0.4.18",
     "js-yaml": "^4.1.0",
     "jsdom": "^26.1.0",
@@ -118,18 +118,18 @@
     "markdown-table": "^3.0.4",
     "nyc": "^17.1.0",
     "path-browserify": "^1.0.1",
-    "prettier": "^3.5.3",
+    "prettier": "^3.6.2",
     "prettier-plugin-jsdoc": "^1.3.3",
     "rimraf": "^6.0.1",
     "rollup-plugin-visualizer": "^6.0.3",
-    "start-server-and-test": "^2.0.13",
+    "start-server-and-test": "^2.1.2",
     "tslib": "^2.8.1",
-    "tsx": "^4.7.3",
+    "tsx": "^4.20.5",
     "typescript": "~5.7.3",
     "typescript-eslint": "^8.38.0",
-    "vite": "^7.0.6",
+    "vite": "^7.0.7",
     "vite-plugin-istanbul": "^7.0.0",
-    "vitest": "^3.0.9"
+    "vitest": "^3.2.4"
   },
   "nyc": {
     "report-dir": "coverage/cypress"

packages/mermaid-example-diagram/package.json

@@ -42,7 +42,7 @@
     "khroma": "^2.1.0"
   },
   "devDependencies": {
-    "concurrently": "^9.1.2",
+    "concurrently": "^9.2.1",
     "mermaid": "workspace:*",
     "rimraf": "^6.0.1"
   },

packages/mermaid-zenuml/package.json

@@ -33,7 +33,7 @@
   ],
   "license": "MIT",
   "dependencies": {
-    "@zenuml/core": "^3.35.2"
+    "@zenuml/core": "^3.41.4"
   },
   "devDependencies": {
     "mermaid": "workspace:^"

packages/mermaid/CHANGELOG.md

@@ -1,24 +1,5 @@
 # mermaid
 
-## 11.12.0
-
-### Minor Changes
-
-- [#6921](https://github.com/mermaid-js/mermaid/pull/6921) [`764b315`](https://github.com/mermaid-js/mermaid/commit/764b315dc16d0359add7c6b8e3ef7592e9bdc09c) Thanks [@quilicicf](https://github.com/quilicicf)! - feat: Add IDs in architecture diagrams
-
-### Patch Changes
-
-- [#6950](https://github.com/mermaid-js/mermaid/pull/6950) [`a957908`](https://github.com/mermaid-js/mermaid/commit/a9579083bfba367a4f4678547ec37ed7b61b9f5b) Thanks [@shubhamparikh2704](https://github.com/shubhamparikh2704)! - chore: Fix mindmap rendering in docs and apply tidytree layout
-
-- [#6826](https://github.com/mermaid-js/mermaid/pull/6826) [`1d36810`](https://github.com/mermaid-js/mermaid/commit/1d3681053b9168354e48e5763023b6305cd1ca72) Thanks [@darshanr0107](https://github.com/darshanr0107)! - fix: Ensure edge label color is applied when using classDef with edge IDs
-
-- [#6945](https://github.com/mermaid-js/mermaid/pull/6945) [`d318f1a`](https://github.com/mermaid-js/mermaid/commit/d318f1a13cd7429334a29c70e449074ec1cb9f68) Thanks [@darshanr0107](https://github.com/darshanr0107)! - fix: Resolve gantt chart crash due to invalid array length
-
-- [#6918](https://github.com/mermaid-js/mermaid/pull/6918) [`cfe9238`](https://github.com/mermaid-js/mermaid/commit/cfe9238882cbe95416db1feea3112456a71b6aaf) Thanks [@shubhamparikh2704](https://github.com/shubhamparikh2704)! - chore: revert marked dependency from ^15.0.7 to ^16.0.0
-  - Reverted marked package version to ^16.0.0 for better compatibility
-  - This is a dependency update that maintains API compatibility
-  - All tests pass with the updated version
-
 ## 11.11.0
 
 ### Minor Changes

packages/mermaid/package.json

@@ -1,6 +1,6 @@
 {
   "name": "mermaid",
-  "version": "11.12.0",
+  "version": "11.11.0",
   "description": "Markdown-ish syntax for generating flowcharts, mindmaps, sequence diagrams, class diagrams, gantt charts, git graphs and more.",
   "type": "module",
   "module": "./dist/mermaid.core.mjs",
@@ -68,10 +68,10 @@
   },
   "dependencies": {
     "@braintree/sanitize-url": "^7.1.1",
-    "@iconify/utils": "^3.0.1",
+    "@iconify/utils": "^3.0.2",
     "@mermaid-js/parser": "workspace:^",
     "@types/d3": "^7.4.3",
-    "cytoscape": "^3.29.3",
+    "cytoscape": "^3.33.1",
     "cytoscape-cose-bilkent": "^4.1.0",
     "cytoscape-fcose": "^2.2.0",
     "d3": "^7.9.0",
@@ -82,7 +82,7 @@
     "katex": "^0.16.22",
     "khroma": "^2.1.0",
     "lodash-es": "^4.17.21",
-    "marked": "^16.2.1",
+    "marked": "^16.3.0",
     "roughjs": "^4.6.6",
     "stylis": "^4.3.6",
     "ts-dedent": "^2.2.0",
@@ -105,9 +105,9 @@
     "@types/stylis": "^4.2.7",
     "@types/uuid": "^10.0.0",
     "ajv": "^8.17.1",
-    "canvas": "^3.1.2",
+    "canvas": "^3.2.0",
     "chokidar": "3.6.0",
-    "concurrently": "^9.1.2",
+    "concurrently": "^9.2.1",
     "csstree-validator": "^4.0.1",
     "globby": "^14.1.0",
     "jison": "^0.4.18",
@@ -116,14 +116,14 @@
     "json-schema-to-typescript": "^15.0.4",
     "micromatch": "^4.0.8",
     "path-browserify": "^1.0.1",
-    "prettier": "^3.5.3",
+    "prettier": "^3.6.2",
     "remark": "^15.0.1",
     "remark-frontmatter": "^5.0.0",
     "remark-gfm": "^4.0.1",
     "rimraf": "^6.0.1",
-    "start-server-and-test": "^2.0.13",
-    "type-fest": "^4.35.0",
-    "typedoc": "^0.28.12",
+    "start-server-and-test": "^2.1.2",
+    "type-fest": "^4.41.0",
+    "typedoc": "^0.28.13",
     "typedoc-plugin-markdown": "^4.8.1",
     "typescript": "~5.7.3",
     "unist-util-flatmap": "^1.0.0",

packages/mermaid/src/diagrams/er/parser/erDiagram.jison

@@ -66,12 +66,15 @@ accDescr\s*"{"\s*                                { this.begin("acc_descr_multili
 \}\|                            return 'ONE_OR_MORE';
 "one"                           return 'ONLY_ONE';
 "only one"                      return 'ONLY_ONE';
-"1"                             return 'ONLY_ONE';
+[0-9]+\.[0-9]+                  return 'DECIMAL_NUM';
+"1"(?=\s+[A-Za-z_"'])           return 'ONLY_ONE';
+"1"                             return 'ENTITY_ONE';
+[0-9]+                          return 'NUM';
 \|\|                            return 'ONLY_ONE';
 o\|                             return 'ZERO_OR_ONE';
 o\{                             return 'ZERO_OR_MORE';
 \|\{                            return 'ONE_OR_MORE';
-\s*u                            return 'MD_PARENT';
+u(?=[\.\-\|])                   return 'MD_PARENT';
 \.\.                            return 'NON_IDENTIFYING';
 \-\-                            return 'IDENTIFYING';
 "to"                            return 'IDENTIFYING';
@@ -80,13 +83,15 @@ o\{                             return 'ZERO_OR_MORE';
 \-\.                            return 'NON_IDENTIFYING';
 <style>([^\x00-\x7F]|\w|\-|\*)+ return 'STYLE_TEXT';
 <style>';'                      return 'SEMI';
-([^\x00-\x7F]|\w|\-|\*)+        return 'UNICODE_TEXT';
-[0-9]                           return 'NUM';
+([^\x00-\x7F]|\w|\-|\*|\.)+      return 'UNICODE_TEXT';
 .                               return yytext[0];
 <<EOF>>                         return 'EOF';
 
 /lex
 
+%left 'ONLY_ONE'
+%left 'ZERO_OR_ONE' 'ZERO_OR_MORE' 'ONE_OR_MORE' 'MD_PARENT'
+
 %start start
 %% /* language grammar */
 
@@ -228,6 +233,9 @@ styleComponent: STYLE_TEXT | NUM | COLON | BRKT;
 entityName
     : 'ENTITY_NAME'      { $$ = $1.replace(/"/g, ''); }
     | 'UNICODE_TEXT' { $$ = $1; }
+    | 'NUM' { $$ = $1; }
+    | 'DECIMAL_NUM' { $$ = $1; }
+    | 'ENTITY_ONE' { $$ = $1; }
     ;
 
 attributes

packages/mermaid/src/diagrams/er/parser/erDiagram.spec.js

@@ -1001,4 +1001,90 @@ describe('when parsing ER diagram it...', function () {
       }
     );
   });
+
+  describe('syntax fixes for special characters and numbers', function () {
+    describe('standalone entity names', function () {
+      it('should allow number "1" as standalone entity', function () {
+        erDiagram.parser.parse(`erDiagram\nCUSTOMER }|..|{ DELIVERY-ADDRESS : has\n1`);
+      });
+
+      it('should allow character "u" as standalone entity', function () {
+        erDiagram.parser.parse(`erDiagram\nCUSTOMER }|..|{ DELIVERY-ADDRESS : has\nu`);
+      });
+
+      it('should allow decimal numbers as standalone entities', function () {
+        erDiagram.parser.parse(`erDiagram\nCUSTOMER }|..|{ DELIVERY-ADDRESS : has\n2.5`);
+        erDiagram.parser.parse(`erDiagram\nCUSTOMER }|..|{ DELIVERY-ADDRESS : has\n1.5`);
+        erDiagram.parser.parse(`erDiagram\nCUSTOMER }|..|{ DELIVERY-ADDRESS : has\n0.1`);
+        erDiagram.parser.parse(`erDiagram\nCUSTOMER }|..|{ DELIVERY-ADDRESS : has\n99.99`);
+      });
+    });
+
+    describe('entity names with attributes', function () {
+      it('should allow "u" as entity name with attributes', function () {
+        erDiagram.parser.parse(`erDiagram\nu {\nstring name\nint id\n}`);
+      });
+
+      it('should allow number "1" as entity name with attributes', function () {
+        erDiagram.parser.parse(`erDiagram\n1 {\nstring name\nint id\n}`);
+      });
+
+      it('should allow decimal numbers as entity names with attributes', function () {
+        erDiagram.parser.parse(`erDiagram\n2.5 {\nstring name\nint id\n}`);
+        erDiagram.parser.parse(`erDiagram\n1.5 {\nstring value\n}`);
+      });
+    });
+
+    describe('entity names in relationships', function () {
+      it('should allow "u" in relationships', function () {
+        erDiagram.parser.parse(`erDiagram\nCUSTOMER ||--|| u : has`);
+        erDiagram.parser.parse(`erDiagram\nu ||--|| ORDER : places`);
+        erDiagram.parser.parse(`erDiagram\nu ||--|| v : connects`);
+      });
+
+      it('should allow numbers in relationships', function () {
+        erDiagram.parser.parse(`erDiagram\nCUSTOMER ||--|| 1 : has`);
+        erDiagram.parser.parse(`erDiagram\n1 ||--|| ORDER : places`);
+        erDiagram.parser.parse(`erDiagram\n1 ||--|| 2 : connects`);
+      });
+
+      it('should allow decimal numbers in relationships', function () {
+        erDiagram.parser.parse(`erDiagram\nCUSTOMER ||--|| 2.5 : has`);
+        erDiagram.parser.parse(`erDiagram\n1.5 ||--|| ORDER : places`);
+        erDiagram.parser.parse(`erDiagram\n2.5 ||--|| 5.5 : connects`);
+      });
+    });
+
+    describe('mixed scenarios', function () {
+      it('should handle complex diagram with special entity names', function () {
+        erDiagram.parser.parse(
+          `erDiagram
+              CUSTOMER ||--o{ 1 : places
+              1 ||--|{ u : contains
+              u {
+                string name
+                int quantity
+              }
+              "2.5" ||--|| ORDER : processes
+              ORDER {
+                int id
+                date created
+              }
+        `
+        );
+      });
+
+      it('should handle attributes with numbers in names (but not starting)', function () {
+        erDiagram.parser.parse(
+          `erDiagram
+              ENTITY {
+                string name1
+                int value2
+                float point3_5
+              }
+        `
+        );
+      });
+    });
+  });
 });

packages/mermaid/src/diagrams/sequence/parser/sequenceDiagram.jison

@@ -78,7 +78,7 @@ accDescr\s*"{"\s*                                { this.begin("acc_descr_multili
 "off"															return 'off';
 ","                                                             return ',';
 ";"                                                             return 'NEWLINE';
-[^+<\->\->:\n,;]+((?!(\-x|\-\-x|\-\)|\-\-\)))[\-]*[^\+<\->\->:\n,;]+)*             { yytext = yytext.trim(); return 'ACTOR'; }
+[^\/\\\+\()\+<\->\->:\n,;]+((?!(\-x|\-\-x|\-\)|\-\-\)|\-\|\\|\-\\|\-\/|\-\/\/|\-\|\/|\/\|\-|\\\|\-|\/\/\-|\\\\\-|\/\|\-|\-\-\|\\|\-\-|\(\)))[\-]*[^\+<\->\->:\n,;]+)*             { yytext = yytext.trim(); return 'ACTOR'; } //final_4.11
 "->>"                                                           return 'SOLID_ARROW';
 "<<->>"                                                           return 'BIDIRECTIONAL_SOLID_ARROW';
 "-->>"                                                          return 'DOTTED_ARROW';
@@ -89,10 +89,36 @@ accDescr\s*"{"\s*                                { this.begin("acc_descr_multili
 \-\-[x]                                                         return 'DOTTED_CROSS';
 \-[\)]                                                          return 'SOLID_POINT';
 \-\-[\)]                                                        return 'DOTTED_POINT';
+
+//normal-dotted
+\-\-\|\\                                                        return 'SOLID_ARROW_TOP_DOTTED';
+\-\-\|\/                                                        return 'SOLID_ARROW_BOTTOM_DOTTED';
+\-\-\\\\                                                        return 'STICK_ARROW_TOP_DOTTED';
+\-\-\/\/                                                        return 'STICK_ARROW_BOTTOM_DOTTED';
+
+//reverse-dotted
+\/\|\-\-                                                          return 'SOLID_ARROW_TOP_REVERSE_DOTTED';
+\\\|\-\-                                                          return 'SOLID_ARROW_BOTTOM_REVERSE_DOTTED';
+\/\/\-\-                                                          return 'STICK_ARROW_TOP_REVERSE_DOTTED';
+\\\\\-\-                                                          return 'STICK_ARROW_BOTTOM_REVERSE_DOTTED';
+
+//normal
+\-\|\\                                                          return 'SOLID_ARROW_TOP';
+\-\|\/                                                          return 'SOLID_ARROW_BOTTOM';
+\-\\\\                                                          return 'STICK_ARROW_TOP';
+\-\/\/                                                          return 'STICK_ARROW_BOTTOM';
+
+//reverse
+\/\|\-                                                          return 'SOLID_ARROW_TOP_REVERSE';
+\\\|\-                                                          return 'SOLID_ARROW_BOTTOM_REVERSE';
+\/\/\-                                                          return 'STICK_ARROW_TOP_REVERSE';
+\\\\\-                                                          return 'STICK_ARROW_BOTTOM_REVERSE';
+
 ":"(?:(?:no)?wrap:)?[^#\n;]*                                    return 'TXT';
 ":"                             								return 'TXT';
 "+"                                                             return '+';
 "-"                                                             return '-';
+"()"                                                            return '()';
 <<EOF>>                                                         return 'NEWLINE';
 .                                                               return 'INVALID';
 
@@ -304,6 +330,20 @@ signal
 	{ $$ = [$1,$4,{type: 'addMessage', from:$1.actor, to:$4.actor, signalType:$2, msg:$5},
 	             {type: 'activeEnd', signalType: yy.LINETYPE.ACTIVE_END, actor: $1.actor}
 	             ]}
+    | actor signaltype '()' actor text2
+	{ $$ = [$1,$4,{type: 'addMessage', from:$1.actor, to:$4.actor, signalType:$2, msg:$5, activate: true, centralConnection: yy.LINETYPE.CENTRAL_CONNECTION},
+	              {type: 'centralConnection', signalType: yy.LINETYPE.CENTRAL_CONNECTION, actor: $4.actor, }
+	             ]}
+    
+	| actor '()' signaltype actor text2
+	{ $$ = [$1,$4,{type: 'addMessage', from:$1.actor, to:$4.actor, signalType:$3, msg:$5, activate: false, centralConnection: yy.LINETYPE.CENTRAL_CONNECTION_REVERSE},
+	              {type: 'centralConnectionReverse', signalType: yy.LINETYPE.CENTRAL_CONNECTION_REVERSE, actor: $1.actor}
+	             ]}
+	| actor '()' signaltype '()' actor text2
+	{ $$ = [$1,$5,{type: 'addMessage', from:$1.actor, to:$5.actor, signalType:$3, msg:$6, activate: true, centralConnection: yy.LINETYPE.CENTRAL_CONNECTION_DUAL},
+	 			 {type: 'centralConnection', signalType: yy.LINETYPE.CENTRAL_CONNECTION, actor: $5.actor, },
+				 {type: 'centralConnectionReverse', signalType: yy.LINETYPE.CENTRAL_CONNECTION_REVERSE, actor: $1.actor}
+	             ]}
 	| actor signaltype actor text2
 	{ $$ = [$1,$3,{type: 'addMessage', from:$1.actor, to:$3.actor, signalType:$2, msg:$4}]}
 	;
@@ -337,7 +377,28 @@ signaltype
 	: SOLID_OPEN_ARROW  { $$ = yy.LINETYPE.SOLID_OPEN; }
 	| DOTTED_OPEN_ARROW { $$ = yy.LINETYPE.DOTTED_OPEN; }
 	| SOLID_ARROW       { $$ = yy.LINETYPE.SOLID; }
-	| BIDIRECTIONAL_SOLID_ARROW       { $$ = yy.LINETYPE.BIDIRECTIONAL_SOLID; }
+	
+	| SOLID_ARROW_TOP    { $$ = yy.LINETYPE.SOLID_TOP; }
+	| SOLID_ARROW_BOTTOM { $$ = yy.LINETYPE.SOLID_BOTTOM; }
+	| STICK_ARROW_TOP    { $$ = yy.LINETYPE.STICK_TOP; }
+	| STICK_ARROW_BOTTOM { $$ = yy.LINETYPE.STICK_BOTTOM; }
+
+	| SOLID_ARROW_TOP_DOTTED    { $$ = yy.LINETYPE.SOLID_TOP_DOTTED; }	
+	| SOLID_ARROW_BOTTOM_DOTTED { $$ = yy.LINETYPE.SOLID_BOTTOM_DOTTED; }
+	| STICK_ARROW_TOP_DOTTED    { $$ = yy.LINETYPE.STICK_TOP_DOTTED; }
+	| STICK_ARROW_BOTTOM_DOTTED { $$ = yy.LINETYPE.STICK_BOTTOM_DOTTED; }
+
+	| SOLID_ARROW_TOP_REVERSE    { $$ = yy.LINETYPE.SOLID_ARROW_TOP_REVERSE; }
+	| SOLID_ARROW_BOTTOM_REVERSE { $$ = yy.LINETYPE.SOLID_ARROW_BOTTOM_REVERSE; }
+	| STICK_ARROW_TOP_REVERSE    { $$ = yy.LINETYPE.STICK_ARROW_TOP_REVERSE; }
+	| STICK_ARROW_BOTTOM_REVERSE { $$ = yy.LINETYPE.STICK_ARROW_BOTTOM_REVERSE; }
+
+	| SOLID_ARROW_TOP_REVERSE_DOTTED    { $$ = yy.LINETYPE.SOLID_ARROW_TOP_REVERSE_DOTTED; }
+	| SOLID_ARROW_BOTTOM_REVERSE_DOTTED { $$ = yy.LINETYPE.SOLID_ARROW_BOTTOM_REVERSE_DOTTED; }
+	| STICK_ARROW_TOP_REVERSE_DOTTED    { $$ = yy.LINETYPE.STICK_ARROW_TOP_REVERSE_DOTTED; }
+	| STICK_ARROW_BOTTOM_REVERSE_DOTTED { $$ = yy.LINETYPE.STICK_ARROW_BOTTOM_REVERSE_DOTTED; }
+
+  | BIDIRECTIONAL_SOLID_ARROW       { $$ = yy.LINETYPE.BIDIRECTIONAL_SOLID; }
 	| DOTTED_ARROW      { $$ = yy.LINETYPE.DOTTED; }
 	| BIDIRECTIONAL_DOTTED_ARROW      { $$ = yy.LINETYPE.BIDIRECTIONAL_DOTTED; }
 	| SOLID_CROSS       { $$ = yy.LINETYPE.SOLID_CROSS; }

packages/mermaid/src/diagrams/sequence/sequenceDb.ts

@@ -64,6 +64,30 @@ const LINETYPE = {
   PAR_OVER_START: 32,
   BIDIRECTIONAL_SOLID: 33,
   BIDIRECTIONAL_DOTTED: 34,
+
+  SOLID_TOP: 41,
+  SOLID_BOTTOM: 42,
+  STICK_TOP: 43,
+  STICK_BOTTOM: 44,
+
+  SOLID_ARROW_TOP_REVERSE: 45,
+  SOLID_ARROW_BOTTOM_REVERSE: 46,
+  STICK_ARROW_TOP_REVERSE: 47,
+  STICK_ARROW_BOTTOM_REVERSE: 48,
+
+  SOLID_TOP_DOTTED: 51,
+  SOLID_BOTTOM_DOTTED: 52,
+  STICK_TOP_DOTTED: 53,
+  STICK_BOTTOM_DOTTED: 54,
+
+  SOLID_ARROW_TOP_REVERSE_DOTTED: 55,
+  SOLID_ARROW_BOTTOM_REVERSE_DOTTED: 56,
+  STICK_ARROW_TOP_REVERSE_DOTTED: 57,
+  STICK_ARROW_BOTTOM_REVERSE_DOTTED: 58,
+
+  CENTRAL_CONNECTION: 59,
+  CENTRAL_CONNECTION_REVERSE: 60,
+  CENTRAL_CONNECTION_DUAL: 61,
 } as const;
 
 const ARROWTYPE = {
@@ -244,7 +268,8 @@ export class SequenceDB implements DiagramDB {
     idTo?: Message['to'],
     message?: { text: string; wrap: boolean },
     messageType?: number,
-    activate = false
+    activate = false,
+    centralConnection?: number
   ) {
     if (messageType === this.LINETYPE.ACTIVE_END) {
       const cnt = this.activationCount(idFrom ?? '');
@@ -271,6 +296,7 @@ export class SequenceDB implements DiagramDB {
       wrap: message?.wrap ?? this.autoWrap(),
       type: messageType,
       activate,
+      centralConnection: centralConnection ?? 0,
     });
     return true;
   }
@@ -563,6 +589,12 @@ export class SequenceDB implements DiagramDB {
         case 'activeStart':
           this.addSignal(param.actor, undefined, undefined, param.signalType);
           break;
+        case 'centralConnection':
+          this.addSignal(param.actor, undefined, undefined, param.signalType);
+          break;
+        case 'centralConnectionReverse':
+          this.addSignal(param.actor, undefined, undefined, param.signalType);
+          break;
         case 'activeEnd':
           this.addSignal(param.actor, undefined, undefined, param.signalType);
           break;
@@ -606,7 +638,14 @@ export class SequenceDB implements DiagramDB {
               this.state.records.lastDestroyed = undefined;
             }
           }
-          this.addSignal(param.from, param.to, param.msg, param.signalType, param.activate);
+          this.addSignal(
+            param.from,
+            param.to,
+            param.msg,
+            param.signalType,
+            param.activate,
+            param.centralConnection
+          );
           break;
         case 'boxStart':
           this.addBox(param.boxData);

packages/mermaid/src/diagrams/sequence/sequenceDiagram.spec.js

@@ -104,6 +104,7 @@ describe('more than one sequence diagram', () => {
       [
         {
           "activate": false,
+          "centralConnection": 0,
           "from": "Alice",
           "id": "0",
           "message": "Hello Bob, how are you?",
@@ -113,6 +114,7 @@ describe('more than one sequence diagram', () => {
         },
         {
           "activate": false,
+          "centralConnection": 0,
           "from": "Bob",
           "id": "1",
           "message": "I am good thanks!",
@@ -131,6 +133,7 @@ describe('more than one sequence diagram', () => {
       [
         {
           "activate": false,
+          "centralConnection": 0,
           "from": "Alice",
           "id": "0",
           "message": "Hello Bob, how are you?",
@@ -140,6 +143,7 @@ describe('more than one sequence diagram', () => {
         },
         {
           "activate": false,
+          "centralConnection": 0,
           "from": "Bob",
           "id": "1",
           "message": "I am good thanks!",
@@ -160,6 +164,7 @@ describe('more than one sequence diagram', () => {
       [
         {
           "activate": false,
+          "centralConnection": 0,
           "from": "Alice",
           "id": "0",
           "message": "Hello John, how are you?",
@@ -169,6 +174,7 @@ describe('more than one sequence diagram', () => {
         },
         {
           "activate": false,
+          "centralConnection": 0,
           "from": "John",
           "id": "1",
           "message": "I am good thanks!",
@@ -181,6 +187,254 @@ describe('more than one sequence diagram', () => {
   });
 });
 
+describe('Central Connection Parsing', () => {
+  describe('when parsing central connection syntax', () => {
+    it('should parse actor ()->>() actor syntax as CENTRAL_CONNECTION_DUAL', async () => {
+      const diagram = await Diagram.fromText(`
+        sequenceDiagram
+        participant Alice
+        participant Bob
+        Alice ()->>() Bob: Hello Bob, how are you?
+      `);
+
+      const messages = diagram.db.getMessages();
+      expect(messages).toHaveLength(3); // addMessage + centralConnection + centralConnectionReverse
+
+      // Find the actual message (type: 'addMessage')
+      const actualMessage = messages.find((msg) => msg.type !== undefined && msg.from && msg.to);
+      expect(actualMessage).toMatchObject({
+        from: 'Alice',
+        to: 'Bob',
+        message: 'Hello Bob, how are you?',
+        centralConnection: 61, // CENTRAL_CONNECTION_DUAL
+        activate: true,
+        type: 0, // SOLID (based on test output)
+      });
+    });
+
+    it('should parse actor ()-->>() actor syntax as CENTRAL_CONNECTION_DUAL', async () => {
+      const diagram = await Diagram.fromText(`
+        sequenceDiagram
+        participant Alice
+        participant Bob
+        Alice ()-->>() Bob: Hello Bob, how are you?
+      `);
+
+      const messages = diagram.db.getMessages();
+      expect(messages).toHaveLength(3); // addMessage + centralConnection + centralConnectionReverse
+
+      const actualMessage = messages.find((msg) => msg.type !== undefined && msg.from && msg.to);
+      expect(actualMessage).toMatchObject({
+        from: 'Alice',
+        to: 'Bob',
+        message: 'Hello Bob, how are you?',
+        centralConnection: 61, // CENTRAL_CONNECTION_DUAL
+        activate: true,
+        type: 1, // DOTTED (based on test output)
+      });
+    });
+
+    it('should parse actor ->>() actor syntax as CENTRAL_CONNECTION', async () => {
+      const diagram = await Diagram.fromText(`
+        sequenceDiagram
+        participant Alice
+        participant Bob
+        Alice ->>() Bob: Hello Bob, how are you?
+      `);
+
+      const messages = diagram.db.getMessages();
+      expect(messages).toHaveLength(2); // addMessage + centralConnection (no activation for this pattern)
+
+      const actualMessage = messages.find((msg) => msg.type !== undefined && msg.from && msg.to);
+      expect(actualMessage).toMatchObject({
+        from: 'Alice',
+        to: 'Bob',
+        message: 'Hello Bob, how are you?',
+        centralConnection: 59, // CENTRAL_CONNECTION
+        activate: true,
+        type: 0, // SOLID (based on actual parsing)
+      });
+    });
+
+    it('should parse actor ()-->> actor syntax as CENTRAL_CONNECTION_REVERSE', async () => {
+      const diagram = await Diagram.fromText(`
+        sequenceDiagram
+        participant Alice
+        participant Bob
+        Alice ()-->> Bob: Hello Bob, how are you?
+      `);
+
+      const messages = diagram.db.getMessages();
+      expect(messages).toHaveLength(2); // addMessage + centralConnectionReverse
+
+      const actualMessage = messages.find((msg) => msg.type !== undefined && msg.from && msg.to);
+      expect(actualMessage).toMatchObject({
+        from: 'Alice',
+        to: 'Bob',
+        message: 'Hello Bob, how are you?',
+        centralConnection: 60, // CENTRAL_CONNECTION_REVERSE
+        activate: false,
+        type: 1, // DOTTED (based on test output)
+      });
+    });
+
+    it('should parse actor ()->> actor syntax as CENTRAL_CONNECTION_REVERSE', async () => {
+      const diagram = await Diagram.fromText(`
+        sequenceDiagram
+        participant Alice
+        participant Bob
+        Alice ()->> Bob: Hello Bob, how are you?
+      `);
+
+      const messages = diagram.db.getMessages();
+      expect(messages).toHaveLength(2); // addMessage + centralConnectionReverse
+
+      const actualMessage = messages.find((msg) => msg.type !== undefined && msg.from && msg.to);
+      expect(actualMessage).toMatchObject({
+        from: 'Alice',
+        to: 'Bob',
+        message: 'Hello Bob, how are you?',
+        centralConnection: 60, // CENTRAL_CONNECTION_REVERSE
+        activate: false,
+        type: 0, // SOLID (based on test output)
+      });
+    });
+
+    it('should parse actor ()<<-->>() actor syntax as CENTRAL_CONNECTION_DUAL', async () => {
+      const diagram = await Diagram.fromText(`
+        sequenceDiagram
+        participant Alice
+        participant Bob
+        Alice ()<<-->>() Bob: Hello Bob, how are you?
+      `);
+
+      const messages = diagram.db.getMessages();
+      expect(messages).toHaveLength(3); // addMessage + centralConnection + centralConnectionReverse
+
+      const actualMessage = messages.find((msg) => msg.type !== undefined && msg.from && msg.to);
+      expect(actualMessage).toMatchObject({
+        from: 'Alice',
+        to: 'Bob',
+        message: 'Hello Bob, how are you?',
+        centralConnection: 61, // CENTRAL_CONNECTION_DUAL
+        activate: true,
+        type: 34, // BIDIRECTIONAL_DOTTED
+      });
+    });
+
+    it('should parse actor ()<<->>() actor syntax as CENTRAL_CONNECTION_DUAL', async () => {
+      const diagram = await Diagram.fromText(`
+        sequenceDiagram
+        participant Alice
+        participant Bob
+        Alice ()<<->>() Bob: Hello Bob, how are you?
+      `);
+
+      const messages = diagram.db.getMessages();
+      expect(messages).toHaveLength(3); // addMessage + centralConnection + centralConnectionReverse
+
+      const actualMessage = messages.find((msg) => msg.type !== undefined && msg.from && msg.to);
+      expect(actualMessage).toMatchObject({
+        from: 'Alice',
+        to: 'Bob',
+        message: 'Hello Bob, how are you?',
+        centralConnection: 61, // CENTRAL_CONNECTION_DUAL
+        activate: true,
+        type: 33, // BIDIRECTIONAL_SOLID
+      });
+    });
+
+    it('should handle multiple central connection types in one diagram', async () => {
+      const diagram = await Diagram.fromText(`
+        sequenceDiagram
+        participant Alice
+        participant Bob
+        participant Charlie
+        Alice ()->>() Bob: Message 1
+        Bob ()-->> Charlie: Message 2
+        Charlie ()<<-->>() Alice: Message 3
+      `);
+
+      const messages = diagram.db.getMessages();
+      expect(messages).toHaveLength(8); // 3 addMessages + 5 central connection markers
+
+      // Filter to get only the actual messages
+      const actualMessages = messages.filter((msg) => msg.type !== undefined && msg.from && msg.to);
+      expect(actualMessages).toHaveLength(3);
+
+      expect(actualMessages[0]).toMatchObject({
+        from: 'Alice',
+        to: 'Bob',
+        centralConnection: 61, // CENTRAL_CONNECTION_DUAL (()->>())
+      });
+
+      expect(actualMessages[1]).toMatchObject({
+        from: 'Bob',
+        to: 'Charlie',
+        centralConnection: 60, // CENTRAL_CONNECTION_REVERSE (()-->>)
+      });
+
+      expect(actualMessages[2]).toMatchObject({
+        from: 'Charlie',
+        to: 'Alice',
+        centralConnection: 61, // CENTRAL_CONNECTION_DUAL (()<<-->>())
+      });
+    });
+
+    it('should handle central connections with different arrow types', async () => {
+      const diagram = await Diagram.fromText(`
+        sequenceDiagram
+        participant Alice
+        participant Bob
+        Alice ()-x() Bob: Cross message
+        Alice ()--x() Bob: Dotted cross message
+      `);
+
+      const messages = diagram.db.getMessages();
+      expect(messages).toHaveLength(6); // 2 addMessages + 4 central connection markers
+
+      const actualMessages = messages.filter((msg) => msg.type !== undefined && msg.from && msg.to);
+      expect(actualMessages).toHaveLength(2);
+
+      expect(actualMessages[0]).toMatchObject({
+        from: 'Alice',
+        to: 'Bob',
+        centralConnection: 61, // CENTRAL_CONNECTION_DUAL (()-x())
+        type: 3, // SOLID_CROSS
+      });
+
+      expect(actualMessages[1]).toMatchObject({
+        from: 'Alice',
+        to: 'Bob',
+        centralConnection: 61, // CENTRAL_CONNECTION_DUAL (()--x())
+        type: 4, // DOTTED_CROSS
+      });
+    });
+
+    it('should not break existing parsing without central connections', async () => {
+      const diagram = await Diagram.fromText(`
+        sequenceDiagram
+        participant Alice
+        participant Bob
+        Alice ->> Bob: Normal message
+        Bob -->> Alice: Normal dotted message
+        Alice -x Bob: Normal cross message
+      `);
+
+      const messages = diagram.db.getMessages();
+      expect(messages).toHaveLength(3);
+
+      messages.forEach((msg) => {
+        expect(msg.centralConnection).toBe(0); // No central connection
+      });
+
+      expect(messages[0].type).toBe(0); // SOLID (based on actual parsing)
+      expect(messages[1].type).toBe(1); // DOTTED (based on actual parsing)
+      expect(messages[2].type).toBe(3); // SOLID_CROSS
+    });
+  });
+});
+
 describe('when parsing a sequenceDiagram', function () {
   let diagram;
   beforeEach(async function () {
@@ -2058,6 +2312,36 @@ Bob->>Alice:Got it!
     expect(messages[0].from).toBe('Alice');
     expect(messages[0].to).toBe('Bob');
   });
+
+  it('1 should parse ', async () => {
+    const diagram = await Diagram.fromText(`
+    sequenceDiagram
+    actor Bob
+    actor Alice
+        Bob -|\\ Alice: Hello Alice, how are you?
+        Bob -|/ Alice: Hello Alice, how are you?
+        Bob -// Alice: Hello Alice, how are you?
+        Bob -\\\\ Alice: Hello Alice, how are you?
+        
+        Bob \\|- Alice: Hello Alice, how are you?
+        Bob /|- Alice: Hello Alice, how are you?
+        Bob //- Alice: Hello Alice, how are you?
+        Bob \\\\- Alice: Hello Alice, how are you?        
+    `);
+
+    const messages = diagram.db.getMessages();
+  });
+
+  it('2 should parse ', async () => {
+    const diagram = await Diagram.fromText(`
+    sequenceDiagram
+    actor Bob
+    actor Alice
+      Alice ()<<->>() Bob: hey?
+    `);
+
+    const messages = diagram.db.getMessages();
+  });
   describe('when parsing extended participant syntax', () => {
     it('should parse participants with different quote styles and whitespace', async () => {
       const diagram = await Diagram.fromText(`

packages/mermaid/src/diagrams/sequence/sequenceRenderer.ts

@@ -282,6 +282,49 @@ const drawNote = async function (elem: any, noteModel: NoteModel) {
   bounds.models.addNote(noteModel);
 };
 
+const drawCentralConnection = function (
+  elem: any,
+  msg: any,
+  msgModel: any,
+  diagObj: Diagram,
+  startx: number,
+  stopx: number,
+  lineStartY: number
+) {
+  const actors = diagObj.db.getActors();
+  const fromActor = actors.get(msg.from);
+  const toActor = actors.get(msg.to);
+  const fromCenter = fromActor.x + fromActor.width / 2;
+  const toCenter = toActor.x + toActor.width / 2;
+
+  const g = elem.append('g');
+
+  const drawCircle = (cx: number) => {
+    g.append('circle')
+      .attr('cx', cx)
+      .attr('cy', lineStartY)
+      .attr('r', 5)
+      .attr('width', 10)
+      .attr('height', 10);
+  };
+
+  const { CENTRAL_CONNECTION, CENTRAL_CONNECTION_REVERSE, CENTRAL_CONNECTION_DUAL } =
+    diagObj.db.LINETYPE;
+
+  switch (msg.centralConnection) {
+    case CENTRAL_CONNECTION:
+      drawCircle(toCenter);
+      break;
+    case CENTRAL_CONNECTION_REVERSE:
+      drawCircle(fromCenter);
+      break;
+    case CENTRAL_CONNECTION_DUAL:
+      drawCircle(fromCenter);
+      drawCircle(toCenter);
+      break;
+  }
+};
+
 const messageFont = (cnf) => {
   return {
     fontFamily: cnf.messageFontFamily,
@@ -367,7 +410,7 @@ async function boundMessage(_diagram, msgModel): Promise<number> {
  * @param lineStartY - The Y coordinate at which the message line starts
  * @param diagObj - The diagram object.
  */
-const drawMessage = async function (diagram, msgModel, lineStartY: number, diagObj: Diagram) {
+const drawMessage = async function (diagram, msgModel, lineStartY: number, diagObj: Diagram, msg) {
   const { startx, stopx, starty, message, type, sequenceIndex, sequenceVisible } = msgModel;
   const textDims = utils.calculateTextDimensions(message, messageFont(conf));
   const textObj = svgDrawCommon.getTextObj();
@@ -433,6 +476,9 @@ const drawMessage = async function (diagram, msgModel, lineStartY: number, diagO
     line.attr('y1', lineStartY);
     line.attr('x2', stopx);
     line.attr('y2', lineStartY);
+    if (hasCentralConnection(msg, diagObj)) {
+      drawCentralConnection(diagram, msg, msgModel, diagObj, startx, stopx, lineStartY);
+    }
   }
   // Make an SVG Container
   // Draw the line
@@ -441,7 +487,15 @@ const drawMessage = async function (diagram, msgModel, lineStartY: number, diagO
     type === diagObj.db.LINETYPE.DOTTED_CROSS ||
     type === diagObj.db.LINETYPE.DOTTED_POINT ||
     type === diagObj.db.LINETYPE.DOTTED_OPEN ||
-    type === diagObj.db.LINETYPE.BIDIRECTIONAL_DOTTED
+    type === diagObj.db.LINETYPE.BIDIRECTIONAL_DOTTED ||
+    type === diagObj.db.LINETYPE.SOLID_TOP_DOTTED ||
+    type === diagObj.db.LINETYPE.SOLID_BOTTOM_DOTTED ||
+    type === diagObj.db.LINETYPE.STICK_TOP_DOTTED ||
+    type === diagObj.db.LINETYPE.STICK_BOTTOM_DOTTED ||
+    type === diagObj.db.LINETYPE.SOLID_ARROW_TOP_REVERSE_DOTTED ||
+    type === diagObj.db.LINETYPE.SOLID_ARROW_BOTTOM_REVERSE_DOTTED ||
+    type === diagObj.db.LINETYPE.STICK_ARROW_TOP_REVERSE_DOTTED ||
+    type === diagObj.db.LINETYPE.STICK_ARROW_BOTTOM_REVERSE_DOTTED
   ) {
     line.style('stroke-dasharray', '3, 3');
     line.attr('class', 'messageLine1');
@@ -457,6 +511,51 @@ const drawMessage = async function (diagram, msgModel, lineStartY: number, diagO
   line.attr('stroke-width', 2);
   line.attr('stroke', 'none'); // handled by theme/css anyway
   line.style('fill', 'none'); // remove any fill colour
+
+  if (type === diagObj.db.LINETYPE.SOLID_TOP || type === diagObj.db.LINETYPE.SOLID_TOP_DOTTED) {
+    line.attr('marker-end', 'url(' + url + '#solidTopArrowHead)');
+  }
+  if (
+    type === diagObj.db.LINETYPE.SOLID_BOTTOM ||
+    type === diagObj.db.LINETYPE.SOLID_BOTTOM_DOTTED
+  ) {
+    line.attr('marker-end', 'url(' + url + '#solidBottomArrowHead)');
+  }
+  if (type === diagObj.db.LINETYPE.STICK_TOP || type === diagObj.db.LINETYPE.STICK_TOP_DOTTED) {
+    line.attr('marker-end', 'url(' + url + '#stickTopArrowHead)');
+  }
+  if (
+    type === diagObj.db.LINETYPE.STICK_BOTTOM ||
+    type === diagObj.db.LINETYPE.STICK_BOTTOM_DOTTED
+  ) {
+    line.attr('marker-end', 'url(' + url + '#stickBottomArrowHead)');
+  }
+
+  if (
+    type === diagObj.db.LINETYPE.SOLID_ARROW_TOP_REVERSE ||
+    type === diagObj.db.LINETYPE.SOLID_ARROW_TOP_REVERSE_DOTTED
+  ) {
+    line.attr('marker-start', 'url(' + url + '#solidBottomArrowHead)');
+  }
+  if (
+    type === diagObj.db.LINETYPE.SOLID_ARROW_BOTTOM_REVERSE ||
+    type === diagObj.db.LINETYPE.SOLID_ARROW_BOTTOM_REVERSE_DOTTED
+  ) {
+    line.attr('marker-start', 'url(' + url + '#solidTopArrowHead)');
+  }
+  if (
+    type === diagObj.db.LINETYPE.STICK_ARROW_TOP_REVERSE ||
+    type === diagObj.db.LINETYPE.STICK_ARROW_TOP_REVERSE_DOTTED
+  ) {
+    line.attr('marker-start', 'url(' + url + '#stickBottomArrowHead)');
+  }
+  if (
+    type === diagObj.db.LINETYPE.STICK_ARROW_BOTTOM_REVERSE ||
+    type === diagObj.db.LINETYPE.STICK_ARROW_BOTTOM_REVERSE_DOTTED
+  ) {
+    line.attr('marker-start', 'url(' + url + '#stickTopArrowHead)');
+  }
+
   if (type === diagObj.db.LINETYPE.SOLID || type === diagObj.db.LINETYPE.DOTTED) {
     line.attr('marker-end', 'url(' + url + '#arrowhead)');
   }
@@ -481,7 +580,18 @@ const drawMessage = async function (diagram, msgModel, lineStartY: number, diagO
       type === diagObj.db.LINETYPE.BIDIRECTIONAL_SOLID ||
       type === diagObj.db.LINETYPE.BIDIRECTIONAL_DOTTED;
 
-    if (isBidirectional) {
+    const isReverseArrowType =
+      type === diagObj.db.LINETYPE.SOLID_ARROW_TOP_REVERSE ||
+      type === diagObj.db.LINETYPE.SOLID_ARROW_TOP_REVERSE_DOTTED ||
+      type === diagObj.db.LINETYPE.SOLID_ARROW_BOTTOM_REVERSE ||
+      type === diagObj.db.LINETYPE.SOLID_ARROW_BOTTOM_REVERSE_DOTTED ||
+      type === diagObj.db.LINETYPE.STICK_ARROW_TOP_REVERSE ||
+      type === diagObj.db.LINETYPE.STICK_ARROW_TOP_REVERSE_DOTTED ||
+      type === diagObj.db.LINETYPE.STICK_ARROW_BOTTOM_REVERSE ||
+      type === diagObj.db.LINETYPE.STICK_ARROW_BOTTOM_REVERSE_DOTTED;
+
+    let x = 0;
+    if (isBidirectional || isReverseArrowType) {
       const SEQUENCE_NUMBER_RADIUS = 6;
 
       if (startx < stopx) {
@@ -489,6 +599,7 @@ const drawMessage = async function (diagram, msgModel, lineStartY: number, diagO
       } else {
         line.attr('x1', startx + SEQUENCE_NUMBER_RADIUS);
       }
+      x = 3.5;
     }
 
     diagram
@@ -498,7 +609,8 @@ const drawMessage = async function (diagram, msgModel, lineStartY: number, diagO
       .attr('x2', startx)
       .attr('y2', lineStartY)
       .attr('stroke-width', 0)
-      .attr('marker-start', 'url(' + url + '#sequencenumber)');
+      .attr('marker-start', 'url(' + url + '#sequencenumber)')
+      .attr('transform', `translate(-${x}, 0)`);
 
     diagram
       .append('text')
@@ -508,7 +620,8 @@ const drawMessage = async function (diagram, msgModel, lineStartY: number, diagO
       .attr('font-size', '12px')
       .attr('text-anchor', 'middle')
       .attr('class', 'sequenceNumber')
-      .text(sequenceIndex);
+      .text(sequenceIndex)
+      .attr('transform', `translate(-${x}, 0)`);
   }
 };
 
@@ -857,6 +970,10 @@ export const draw = async function (_text: string, id: string, _version: string,
   svgDraw.insertArrowCrossHead(diagram);
   svgDraw.insertArrowFilledHead(diagram);
   svgDraw.insertSequenceNumber(diagram);
+  svgDraw.insertSolidTopArrowHead(diagram);
+  svgDraw.insertSolidBottomArrowHead(diagram);
+  svgDraw.insertStickTopArrowHead(diagram);
+  svgDraw.insertStickBottomArrowHead(diagram);
 
   /**
    * @param msg - The message to draw.
@@ -897,6 +1014,12 @@ export const draw = async function (_text: string, id: string, _version: string,
       case diagObj.db.LINETYPE.ACTIVE_START:
         bounds.newActivation(msg, diagram, actors);
         break;
+      case diagObj.db.LINETYPE.CENTRAL_CONNECTION:
+        bounds.newActivation(msg, diagram, actors);
+        break;
+      case diagObj.db.LINETYPE.CENTRAL_CONNECTION_REVERSE:
+        bounds.newActivation(msg, diagram, actors);
+        break;
       case diagObj.db.LINETYPE.ACTIVE_END:
         activeEnd(msg, bounds.getVerticalPos());
         break;
@@ -1055,7 +1178,7 @@ export const draw = async function (_text: string, id: string, _version: string,
             createdActors,
             destroyedActors
           );
-          messagesToDraw.push({ messageModel: msgModel, lineStartY: lineStartY });
+          messagesToDraw.push({ messageModel: msgModel, lineStartY: lineStartY, msg });
           bounds.models.addMessage(msgModel);
         } catch (e) {
           log.error('error while drawing message', e);
@@ -1068,6 +1191,27 @@ export const draw = async function (_text: string, id: string, _version: string,
         diagObj.db.LINETYPE.SOLID_OPEN,
         diagObj.db.LINETYPE.DOTTED_OPEN,
         diagObj.db.LINETYPE.SOLID,
+
+        diagObj.db.LINETYPE.SOLID_TOP,
+        diagObj.db.LINETYPE.SOLID_BOTTOM,
+        diagObj.db.LINETYPE.STICK_TOP,
+        diagObj.db.LINETYPE.STICK_BOTTOM,
+
+        diagObj.db.LINETYPE.SOLID_TOP_DOTTED,
+        diagObj.db.LINETYPE.SOLID_BOTTOM_DOTTED,
+        diagObj.db.LINETYPE.STICK_TOP_DOTTED,
+        diagObj.db.LINETYPE.STICK_BOTTOM_DOTTED,
+
+        diagObj.db.LINETYPE.SOLID_ARROW_TOP_REVERSE,
+        diagObj.db.LINETYPE.SOLID_ARROW_BOTTOM_REVERSE,
+        diagObj.db.LINETYPE.STICK_ARROW_TOP_REVERSE,
+        diagObj.db.LINETYPE.STICK_ARROW_BOTTOM_REVERSE,
+
+        diagObj.db.LINETYPE.SOLID_ARROW_TOP_REVERSE_DOTTED,
+        diagObj.db.LINETYPE.SOLID_ARROW_BOTTOM_REVERSE_DOTTED,
+        diagObj.db.LINETYPE.STICK_ARROW_TOP_REVERSE_DOTTED,
+        diagObj.db.LINETYPE.STICK_ARROW_BOTTOM_REVERSE_DOTTED,
+
         diagObj.db.LINETYPE.DOTTED,
         diagObj.db.LINETYPE.SOLID_CROSS,
         diagObj.db.LINETYPE.DOTTED_CROSS,
@@ -1087,7 +1231,7 @@ export const draw = async function (_text: string, id: string, _version: string,
   await drawActors(diagram, actors, actorKeys, false);
 
   for (const e of messagesToDraw) {
-    await drawMessage(diagram, e.messageModel, e.lineStartY, diagObj);
+    await drawMessage(diagram, e.messageModel, e.lineStartY, diagObj, e.msg);
   }
   if (conf.mirrorActors) {
     await drawActors(diagram, actors, actorKeys, true);
@@ -1461,12 +1605,85 @@ const buildNoteModel = async function (msg, actors, diagObj) {
   return noteModel;
 };
 
+// Central connection positioning constants
+const CENTRAL_CONNECTION_BASE_OFFSET = 4;
+const CENTRAL_CONNECTION_BIDIRECTIONAL_OFFSET = 6;
+
+/**
+ * Check if a message has central connection
+ * @param msg - The message object
+ * @param diagObj - The diagram object containing LINETYPE constants
+ * @returns True if the message has any type of central connection
+ */
+const hasCentralConnection = function (msg, diagObj) {
+  const { CENTRAL_CONNECTION, CENTRAL_CONNECTION_REVERSE, CENTRAL_CONNECTION_DUAL } =
+    diagObj.db.LINETYPE;
+  return [CENTRAL_CONNECTION, CENTRAL_CONNECTION_REVERSE, CENTRAL_CONNECTION_DUAL].includes(
+    msg.centralConnection
+  );
+};
+
+/**
+ * Calculate the positioning offset for central connection arrows
+ * @param msg - The message object
+ * @param diagObj - The diagram object containing LINETYPE constants
+ * @param isArrowToRight - Whether the arrow is pointing to the right
+ * @returns The offset to apply to startx position
+ */
+const calculateCentralConnectionOffset = function (msg, diagObj, isArrowToRight) {
+  const {
+    CENTRAL_CONNECTION_REVERSE,
+    CENTRAL_CONNECTION_DUAL,
+    BIDIRECTIONAL_SOLID,
+    BIDIRECTIONAL_DOTTED,
+  } = diagObj.db.LINETYPE;
+
+  let offset = 0;
+
+  if (
+    msg.centralConnection === CENTRAL_CONNECTION_REVERSE ||
+    msg.centralConnection === CENTRAL_CONNECTION_DUAL
+  ) {
+    offset += CENTRAL_CONNECTION_BASE_OFFSET;
+  }
+
+  if (
+    msg.centralConnection === CENTRAL_CONNECTION_DUAL &&
+    (msg.type === BIDIRECTIONAL_SOLID || msg.type === BIDIRECTIONAL_DOTTED)
+  ) {
+    offset += isArrowToRight ? 0 : -CENTRAL_CONNECTION_BIDIRECTIONAL_OFFSET;
+  }
+
+  return offset;
+};
+
 const buildMessageModel = function (msg, actors, diagObj) {
   if (
     ![
       diagObj.db.LINETYPE.SOLID_OPEN,
       diagObj.db.LINETYPE.DOTTED_OPEN,
       diagObj.db.LINETYPE.SOLID,
+
+      diagObj.db.LINETYPE.SOLID_TOP,
+      diagObj.db.LINETYPE.SOLID_BOTTOM,
+      diagObj.db.LINETYPE.STICK_TOP,
+      diagObj.db.LINETYPE.STICK_BOTTOM,
+
+      diagObj.db.LINETYPE.SOLID_TOP_DOTTED,
+      diagObj.db.LINETYPE.SOLID_BOTTOM_DOTTED,
+      diagObj.db.LINETYPE.STICK_TOP_DOTTED,
+      diagObj.db.LINETYPE.STICK_BOTTOM_DOTTED,
+
+      diagObj.db.LINETYPE.SOLID_ARROW_TOP_REVERSE,
+      diagObj.db.LINETYPE.SOLID_ARROW_BOTTOM_REVERSE,
+      diagObj.db.LINETYPE.STICK_ARROW_TOP_REVERSE,
+      diagObj.db.LINETYPE.STICK_ARROW_BOTTOM_REVERSE,
+
+      diagObj.db.LINETYPE.SOLID_ARROW_TOP_REVERSE_DOTTED,
+      diagObj.db.LINETYPE.SOLID_ARROW_BOTTOM_REVERSE_DOTTED,
+      diagObj.db.LINETYPE.STICK_ARROW_TOP_REVERSE_DOTTED,
+      diagObj.db.LINETYPE.STICK_ARROW_BOTTOM_REVERSE_DOTTED,
+
       diagObj.db.LINETYPE.DOTTED,
       diagObj.db.LINETYPE.SOLID_CROSS,
       diagObj.db.LINETYPE.DOTTED_CROSS,
@@ -1484,6 +1701,8 @@ const buildMessageModel = function (msg, actors, diagObj) {
   let startx = isArrowToRight ? fromRight : fromLeft;
   let stopx = isArrowToRight ? toLeft : toRight;
 
+  // Apply central connection positioning adjustments
+  startx += calculateCentralConnectionOffset(msg, diagObj, isArrowToRight);
   // As the line width is considered, the left and right values will be off by 2.
   const isArrowToActivation = Math.abs(toLeft - toRight) > 2;
 
@@ -1517,7 +1736,30 @@ const buildMessageModel = function (msg, actors, diagObj) {
      * Shorten the length of arrow at the end and move the marker forward (using refX) to have a clean arrowhead
      * This is not required for open arrows that don't have arrowheads
      */
-    if (![diagObj.db.LINETYPE.SOLID_OPEN, diagObj.db.LINETYPE.DOTTED_OPEN].includes(msg.type)) {
+    if (
+      ![
+        diagObj.db.LINETYPE.SOLID_OPEN,
+        diagObj.db.LINETYPE.DOTTED_OPEN,
+
+        diagObj.db.LINETYPE.STICK_TOP,
+        diagObj.db.LINETYPE.STICK_BOTTOM,
+
+        diagObj.db.LINETYPE.STICK_TOP_DOTTED,
+        diagObj.db.LINETYPE.STICK_BOTTOM_DOTTED,
+
+        diagObj.db.LINETYPE.SOLID_ARROW_TOP_REVERSE_DOTTED,
+        diagObj.db.LINETYPE.SOLID_ARROW_BOTTOM_REVERSE_DOTTED,
+
+        diagObj.db.LINETYPE.STICK_ARROW_TOP_REVERSE,
+        diagObj.db.LINETYPE.STICK_ARROW_BOTTOM_REVERSE,
+
+        diagObj.db.LINETYPE.STICK_ARROW_TOP_REVERSE_DOTTED,
+        diagObj.db.LINETYPE.STICK_ARROW_BOTTOM_REVERSE_DOTTED,
+
+        diagObj.db.LINETYPE.SOLID_ARROW_TOP_REVERSE,
+        diagObj.db.LINETYPE.SOLID_ARROW_BOTTOM_REVERSE,
+      ].includes(msg.type)
+    ) {
       stopx += adjustValue(3);
     }
 
@@ -1525,9 +1767,14 @@ const buildMessageModel = function (msg, actors, diagObj) {
      * Shorten start position of bidirectional arrow to accommodate for second arrowhead
      */
     if (
-      [diagObj.db.LINETYPE.BIDIRECTIONAL_SOLID, diagObj.db.LINETYPE.BIDIRECTIONAL_DOTTED].includes(
-        msg.type
-      )
+      [
+        diagObj.db.LINETYPE.BIDIRECTIONAL_SOLID,
+        diagObj.db.LINETYPE.BIDIRECTIONAL_DOTTED,
+        diagObj.db.LINETYPE.SOLID_ARROW_TOP_REVERSE_DOTTED,
+        diagObj.db.LINETYPE.SOLID_ARROW_BOTTOM_REVERSE_DOTTED,
+        diagObj.db.LINETYPE.SOLID_ARROW_TOP_REVERSE,
+        diagObj.db.LINETYPE.SOLID_ARROW_BOTTOM_REVERSE,
+      ].includes(msg.type)
     ) {
       startx -= adjustValue(3);
     }

packages/mermaid/src/diagrams/sequence/svgDraw.js

@@ -1709,6 +1709,77 @@ const _drawMenuItemTextCandidateFunc = (function () {
   };
 })();
 
+/**
+ * Setup arrow head and define the marker. The result is appended to the svg.
+ *
+ * @param elem
+ */
+export const insertSolidTopArrowHead = function (elem) {
+  elem
+    .append('defs')
+    .append('marker')
+    .attr('id', 'solidTopArrowHead')
+    .attr('refX', 7.9)
+    .attr('refY', 7.25)
+    .attr('markerUnits', 'userSpaceOnUse')
+    .attr('markerWidth', 12)
+    .attr('markerHeight', 12)
+    .attr('orient', 'auto-start-reverse')
+    .append('path')
+    .attr('d', 'M 0 0 L 10 8 L 0 8 z'); // this is actual shape for arrowhead
+};
+
+export const insertSolidBottomArrowHead = function (elem) {
+  elem
+    .append('defs')
+    .append('marker')
+    .attr('id', 'solidBottomArrowHead')
+    .attr('refX', 7.9)
+    .attr('refY', 0.75)
+    .attr('markerUnits', 'userSpaceOnUse')
+    .attr('markerWidth', 12)
+    .attr('markerHeight', 12)
+    .attr('orient', 'auto-start-reverse')
+    .append('path')
+    .attr('d', 'M 0 0 L 10 0 L 0 8 z');
+};
+
+export const insertStickTopArrowHead = function (elem) {
+  elem
+    .append('defs')
+    .append('marker')
+    .attr('id', 'stickTopArrowHead')
+    .attr('refX', 7.5)
+    .attr('refY', 7)
+    .attr('markerUnits', 'userSpaceOnUse')
+    .attr('markerWidth', 12)
+    .attr('markerHeight', 12)
+    .attr('orient', 'auto-start-reverse')
+    .append('path')
+    .attr('d', 'M 0 0 L 7 7')
+    .attr('stroke', 'black')
+    .attr('stroke-width', 1.5)
+    .attr('fill', 'none');
+};
+
+export const insertStickBottomArrowHead = function (elem) {
+  elem
+    .append('defs')
+    .append('marker')
+    .attr('id', 'stickBottomArrowHead')
+    .attr('refX', 7.5)
+    .attr('refY', 0)
+    .attr('markerUnits', 'userSpaceOnUse')
+    .attr('markerWidth', 12)
+    .attr('markerHeight', 12)
+    .attr('orient', 'auto-start-reverse')
+    .append('path')
+    .attr('d', 'M 0 7 L 7 0')
+    .attr('stroke', 'black')
+    .attr('stroke-width', 1.5)
+    .attr('fill', 'none');
+};
+
 export default {
   drawRect,
   drawText,
@@ -1731,4 +1802,8 @@ export default {
   getNoteRect,
   fixLifeLineHeights,
   sanitizeUrl,
+  insertSolidTopArrowHead,
+  insertSolidBottomArrowHead,
+  insertStickTopArrowHead,
+  insertStickBottomArrowHead,
 };

packages/mermaid/src/diagrams/sequence/types.ts

@@ -35,6 +35,7 @@ export interface Message {
   type?: number;
   activate?: boolean;
   placement?: string;
+  centralConnection?: number;
 }
 
 export interface AddMessageParams {
@@ -50,6 +51,8 @@ export interface AddMessageParams {
     | 'destroyParticipant'
     | 'activeStart'
     | 'activeEnd'
+    | 'centralConnection'
+    | 'centralConnectionReverse'
     | 'addNote'
     | 'addLinks'
     | 'addALink'

packages/mermaid/src/docs/package.json

@@ -17,7 +17,7 @@
   },
   "dependencies": {
     "@mdi/font": "^7.4.47",
-    "@vueuse/core": "^13.1.0",
+    "@vueuse/core": "^13.9.0",
     "font-awesome": "^4.7.0",
     "jiti": "^2.4.2",
     "mermaid": "workspace:^",
@@ -25,17 +25,17 @@
   },
   "devDependencies": {
     "@iconify-json/carbon": "^1.2.13",
-    "@unocss/reset": "^66.0.0",
+    "@unocss/reset": "^66.5.1",
     "@vite-pwa/vitepress": "^1.0.0",
     "@vitejs/plugin-vue": "^6.0.1",
     "fast-glob": "^3.3.3",
     "https-localhost": "^4.7.1",
     "pathe": "^2.0.3",
-    "unocss": "^66.4.2",
-    "unplugin-vue-components": "^28.4.0",
-    "vite": "^7.0.0",
-    "vite-plugin-pwa": "^1.0.0",
-    "vitepress": "1.6.3",
+    "unocss": "^66.5.1",
+    "unplugin-vue-components": "^28.4.1",
+    "vite": "^7.0.7",
+    "vite-plugin-pwa": "^1.0.3",
+    "vitepress": "1.6.4",
     "workbox-window": "^7.3.0"
   }
 }

packages/mermaid/src/docs/syntax/sequenceDiagram.md

@@ -216,7 +216,11 @@ Messages can be of two displayed either solid or with a dotted line.
 [Actor][Arrow][Actor]:Message text
 ```
 
-There are ten types of arrows currently supported:
+Lines can be solid or dotted, and can end with various types of arrowheads, crosses, or open arrows.
+
+#### Supported Arrow Types
+
+**Standard Arrow Types**
 
 | Type     | Description                                          |
 | -------- | ---------------------------------------------------- |
@@ -231,6 +235,49 @@ There are ten types of arrows currently supported:
 | `-)`     | Solid line with an open arrow at the end (async)     |
 | `--)`    | Dotted line with a open arrow at the end (async)     |
 
+**Half-Arrows (v<MERMAID_RELEASE_VERSION>+)**
+
+The following half-arrow types are supported for more expressive sequence diagrams. Both solid and dotted variants are available by increasing the number of dashes (`-` → `--`).
+
+---
+
+| Type    | Description                                          |
+| ------- | ---------------------------------------------------- |
+| `-\|\`  | Solid line with top half arrowhead                   |
+| `--\|\` | Dotted line with top half arrowhead                  |
+| `-\|/`  | Solid line with bottom half arrowhead                |
+| `--\|/` | Dotted line with bottom half arrowhead               |
+| `/\|-`  | Solid line with reverse top half arrowhead           |
+| `/\|--` | Dotted line with reverse top half arrowhead          |
+| `\\-`   | Solid line with reverse bottom half arrowhead        |
+| `\\--`  | Dotted line with reverse bottom half arrowhead       |
+| `-\\`   | Solid line with top stick half arrowhead             |
+| `--\\`  | Dotted line with top stick half arrowhead            |
+| `-//`   | Solid line with bottom stick half arrowhead          |
+| `--//`  | Dotted line with bottom stick half arrowhead         |
+| `//-`   | Solid line with reverse top stick half arrowhead     |
+| `//--`  | Dotted line with reverse top stick half arrowhead    |
+| `\\-`   | Solid line with reverse bottom stick half arrowhead  |
+| `\\--`  | Dotted line with reverse bottom stick half arrowhead |
+
+## Central Connections (v<MERMAID_RELEASE_VERSION>+)
+
+Mermaid sequence diagrams support **central lifeline connections** using a `()`.
+This is useful to represent messages or signals that connect to a central point, rather than from one actor directly to another.
+
+To indicate a central connection, append `()` to the arrow syntax.
+
+#### Basic Syntax
+
+```mermaid-example
+sequenceDiagram
+    participant Alice
+    participant John
+    Alice->>()John: Hello John
+    Alice()->>John: How are you?
+    John()->>()Alice: Great!
+```
+
 ## Activations
 
 It is possible to activate and deactivate an actor. (de)activation can be dedicated declarations:

packages/mermaid/src/mermaid.spec.ts

@@ -207,7 +207,7 @@ describe('when using mermaid and ', () => {
         [Error: Parse error on line 2:
         ...equenceDiagramAlice:->Bob: Hello Bob, h...
         ----------------------^
-        Expecting 'SOLID_OPEN_ARROW', 'DOTTED_OPEN_ARROW', 'SOLID_ARROW', 'BIDIRECTIONAL_SOLID_ARROW', 'DOTTED_ARROW', 'BIDIRECTIONAL_DOTTED_ARROW', 'SOLID_CROSS', 'DOTTED_CROSS', 'SOLID_POINT', 'DOTTED_POINT', got 'TXT']
+        Expecting '()', 'SOLID_OPEN_ARROW', 'DOTTED_OPEN_ARROW', 'SOLID_ARROW', 'SOLID_ARROW_TOP', 'SOLID_ARROW_BOTTOM', 'STICK_ARROW_TOP', 'STICK_ARROW_BOTTOM', 'SOLID_ARROW_TOP_DOTTED', 'SOLID_ARROW_BOTTOM_DOTTED', 'STICK_ARROW_TOP_DOTTED', 'STICK_ARROW_BOTTOM_DOTTED', 'SOLID_ARROW_TOP_REVERSE', 'SOLID_ARROW_BOTTOM_REVERSE', 'STICK_ARROW_TOP_REVERSE', 'STICK_ARROW_BOTTOM_REVERSE', 'SOLID_ARROW_TOP_REVERSE_DOTTED', 'SOLID_ARROW_BOTTOM_REVERSE_DOTTED', 'STICK_ARROW_TOP_REVERSE_DOTTED', 'STICK_ARROW_BOTTOM_REVERSE_DOTTED', 'BIDIRECTIONAL_SOLID_ARROW', 'DOTTED_ARROW', 'BIDIRECTIONAL_DOTTED_ARROW', 'SOLID_CROSS', 'DOTTED_CROSS', 'SOLID_POINT', 'DOTTED_POINT', got 'TXT']
       `);
     });
 

packages/tiny/CHANGELOG.md

@@ -1,24 +1,5 @@
 # mermaid
 
-## 11.12.0
-
-### Minor Changes
-
-- [#6921](https://github.com/mermaid-js/mermaid/pull/6921) [`764b315`](https://github.com/mermaid-js/mermaid/commit/764b315dc16d0359add7c6b8e3ef7592e9bdc09c) Thanks [@quilicicf](https://github.com/quilicicf)! - feat: Add IDs in architecture diagrams
-
-### Patch Changes
-
-- [#6950](https://github.com/mermaid-js/mermaid/pull/6950) [`a957908`](https://github.com/mermaid-js/mermaid/commit/a9579083bfba367a4f4678547ec37ed7b61b9f5b) Thanks [@shubhamparikh2704](https://github.com/shubhamparikh2704)! - chore: Fix mindmap rendering in docs and apply tidytree layout
-
-- [#6826](https://github.com/mermaid-js/mermaid/pull/6826) [`1d36810`](https://github.com/mermaid-js/mermaid/commit/1d3681053b9168354e48e5763023b6305cd1ca72) Thanks [@darshanr0107](https://github.com/darshanr0107)! - fix: Ensure edge label color is applied when using classDef with edge IDs
-
-- [#6945](https://github.com/mermaid-js/mermaid/pull/6945) [`d318f1a`](https://github.com/mermaid-js/mermaid/commit/d318f1a13cd7429334a29c70e449074ec1cb9f68) Thanks [@darshanr0107](https://github.com/darshanr0107)! - fix: Resolve gantt chart crash due to invalid array length
-
-- [#6918](https://github.com/mermaid-js/mermaid/pull/6918) [`cfe9238`](https://github.com/mermaid-js/mermaid/commit/cfe9238882cbe95416db1feea3112456a71b6aaf) Thanks [@shubhamparikh2704](https://github.com/shubhamparikh2704)! - chore: revert marked dependency from ^15.0.7 to ^16.0.0
-  - Reverted marked package version to ^16.0.0 for better compatibility
-  - This is a dependency update that maintains API compatibility
-  - All tests pass with the updated version
-
 ## 11.11.0
 
 ### Minor Changes

packages/tiny/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@mermaid-js/tiny",
-  "version": "11.12.0",
+  "version": "11.11.0",
   "description": "Tiny version of mermaid",
   "type": "commonjs",
   "main": "./dist/mermaid.tiny.js",