feat(er): add entity name alias

packages/mermaid/src/diagrams/er/erDb.js

@@ -32,9 +32,9 @@ export const parseDirective = function (statement, context, type) {
   mermaidAPI.parseDirective(this, statement, context, type);
 };
 
-const addEntity = function (name) {
+const addEntity = function (name, alias = undefined) {
   if (entities[name] === undefined) {
-    entities[name] = { attributes: [] };
+    entities[name] = { attributes: [], alias: alias };
     log.info('Added new entity :', name);
   }
 

packages/mermaid/src/diagrams/er/erRenderer.js

@@ -326,7 +326,7 @@ const drawEntities = function (svgNode, entities, graph) {
       .style('text-anchor', 'middle')
       .style('font-family', getConfig().fontFamily)
       .style('font-size', conf.fontSize + 'px')
-      .text(entityName);
+      .text(entities[entityName].alias || entityName);
 
     const { width: entityWidth, height: entityHeight } = drawAttributes(
       groupNode,

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

@@ -62,6 +62,7 @@ o\{                             return 'ZERO_OR_MORE';
 \-\-                            return 'IDENTIFYING';
 "to"                            return 'IDENTIFYING';
 "optionally to"                 return 'NON_IDENTIFYING';
+"as"                            return 'ALIAS';
 \.\-                            return 'NON_IDENTIFYING';
 \-\.                            return 'NON_IDENTIFYING';
 [A-Za-z][A-Za-z0-9\-_]*         return 'ALPHANUM';
@@ -113,6 +114,15 @@ statement
       }
     | entityName BLOCK_START BLOCK_STOP { yy.addEntity($1); }
     | entityName { yy.addEntity($1); }
+    | entityName ALIAS entityName BLOCK_START attributes BLOCK_STOP
+      {
+          /* console.log('detected block'); */
+          yy.addEntity($1, $3);
+          yy.addAttributes($1, $5);
+          /* console.log('handled block'); */
+      }
+    | entityName ALIAS entityName BLOCK_START BLOCK_STOP { yy.addEntity($1, $3); }
+    | entityName ALIAS entityName { yy.addEntity($1, $3); }
     | title title_value  { $$=$2.trim();yy.setAccTitle($$); }
     | acc_title acc_title_value  { $$=$2.trim();yy.setAccTitle($$); }
     | acc_descr acc_descr_value  { $$=$2.trim();yy.setAccDescription($$); }

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

@@ -133,6 +133,15 @@ describe('when parsing ER diagram it...', function () {
       const entities = erDb.getEntities();
       expect(entities.hasOwnProperty(hyphensUnderscore)).toBe(true);
     });
+
+    it('can have an alias', function () {
+      const entity = 'foo';
+      const alias = 'bar';
+      erDiagram.parser.parse(`erDiagram\n${entity} as "${alias}"\n`);
+      const entities = erDb.getEntities();
+      expect(entities.hasOwnProperty(entity)).toBe(true);
+      expect(entities[entity].alias).toBe(alias);
+    });
   });
 
   describe('attribute name', () => {

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

@@ -144,6 +144,22 @@ erDiagram
 
 The `type` values must begin with an alphabetic character and may contain digits, hyphens, underscores, parentheses and square brackets. The `name` values follow a similar format to `type`, but may start with an asterisk as another option to indicate an attribute is a primary key. Other than that, there are no restrictions, and there is no implicit set of valid data types.
 
+### Entity Name Aliases
+
+An alias can be added to an entity using `as` keyword. If provided, the alias will be showed in the diagram instead of the entity name.
+
+```mermaid-example
+erDiagram
+    p as Person {
+        string firstName
+        string lastName
+    }
+    a as "Customer Account" {
+        string email
+    }
+    p ||--o| a : has
+```
+
 #### Attribute Keys and Comments
 
 Attributes may also have a `key` or comment defined. Keys can be `PK`, `FK` or `UK`, for Primary Key, Foreign Key or Unique Key. To specify multiple key constraints on a single attribute, separate them with a comma (e.g., `PK, FK`).. A `comment` is defined by double quotes at the end of an attribute. Comments themselves cannot have double-quote characters in them.