diff --git a/packages/mermaid/src/diagrams/requirement/requirementDb.ts b/packages/mermaid/src/diagrams/requirement/requirementDb.ts
index 76787fd8f..972c5e44e 100644
--- a/packages/mermaid/src/diagrams/requirement/requirementDb.ts
+++ b/packages/mermaid/src/diagrams/requirement/requirementDb.ts
@@ -1,4 +1,5 @@
 import { getConfig } from '../../diagram-api/diagramAPI.js';
+import type { DiagramDB } from '../../diagram-api/types.js';
 import { log } from '../../logger.js';
 import type { Node, Edge } from '../../rendering-util/types.js';
 
@@ -22,320 +23,327 @@ import type {
   VerifyType,
 } from './types.js';
 
-const RequirementType = {
-  REQUIREMENT: 'Requirement',
-  FUNCTIONAL_REQUIREMENT: 'Functional Requirement',
-  INTERFACE_REQUIREMENT: 'Interface Requirement',
-  PERFORMANCE_REQUIREMENT: 'Performance Requirement',
-  PHYSICAL_REQUIREMENT: 'Physical Requirement',
-  DESIGN_CONSTRAINT: 'Design Constraint',
-};
+export class RequirementDB implements DiagramDB {
+  private relations: Relation[] = [];
+  private latestRequirement: Requirement = this.getInitialRequirement();
+  private requirements = new Map<string, Requirement>();
+  private latestElement: Element = this.getInitialElement();
+  private elements = new Map<string, Element>();
+  private classes = new Map<string, RequirementClass>();
+  private direction = 'TB';
 
-const RiskLevel = {
-  LOW_RISK: 'Low',
-  MED_RISK: 'Medium',
-  HIGH_RISK: 'High',
-};
+  private RequirementType = {
+    REQUIREMENT: 'Requirement',
+    FUNCTIONAL_REQUIREMENT: 'Functional Requirement',
+    INTERFACE_REQUIREMENT: 'Interface Requirement',
+    PERFORMANCE_REQUIREMENT: 'Performance Requirement',
+    PHYSICAL_REQUIREMENT: 'Physical Requirement',
+    DESIGN_CONSTRAINT: 'Design Constraint',
+  };
 
-const VerifyType = {
-  VERIFY_ANALYSIS: 'Analysis',
-  VERIFY_DEMONSTRATION: 'Demonstration',
-  VERIFY_INSPECTION: 'Inspection',
-  VERIFY_TEST: 'Test',
-};
+  private RiskLevel = {
+    LOW_RISK: 'Low',
+    MED_RISK: 'Medium',
+    HIGH_RISK: 'High',
+  };
 
-const Relationships = {
-  CONTAINS: 'contains',
-  COPIES: 'copies',
-  DERIVES: 'derives',
-  SATISFIES: 'satisfies',
-  VERIFIES: 'verifies',
-  REFINES: 'refines',
-  TRACES: 'traces',
-};
+  private VerifyType = {
+    VERIFY_ANALYSIS: 'Analysis',
+    VERIFY_DEMONSTRATION: 'Demonstration',
+    VERIFY_INSPECTION: 'Inspection',
+    VERIFY_TEST: 'Test',
+  };
 
-let direction = 'TB';
-const getDirection = () => direction;
-const setDirection = (dir: string) => {
-  direction = dir;
-};
+  private Relationships = {
+    CONTAINS: 'contains',
+    COPIES: 'copies',
+    DERIVES: 'derives',
+    SATISFIES: 'satisfies',
+    VERIFIES: 'verifies',
+    REFINES: 'refines',
+    TRACES: 'traces',
+  };
 
-const getInitialRequirement = (): Requirement => ({
-  requirementId: '',
-  text: '',
-  risk: '' as RiskLevel,
-  verifyMethod: '' as VerifyType,
-  name: '',
-  type: '' as RequirementType,
-  cssStyles: [],
-  classes: ['default'],
-});
+  constructor() {
+    this.clear();
 
-const getInitialElement = (): Element => ({
-  name: '',
-  type: '',
-  docRef: '',
-  cssStyles: [],
-  classes: ['default'],
-});
+    // Needed for JISON since it only supports direct properties
+    this.setDirection = this.setDirection.bind(this);
+    this.addRequirement = this.addRequirement.bind(this);
+    this.setNewReqId = this.setNewReqId.bind(this);
+    this.setNewReqRisk = this.setNewReqRisk.bind(this);
+    this.setNewReqText = this.setNewReqText.bind(this);
+    this.setNewReqVerifyMethod = this.setNewReqVerifyMethod.bind(this);
+    this.addElement = this.addElement.bind(this);
+    this.setNewElementType = this.setNewElementType.bind(this);
+    this.setNewElementDocRef = this.setNewElementDocRef.bind(this);
+    this.addRelationship = this.addRelationship.bind(this);
+    this.setCssStyle = this.setCssStyle.bind(this);
+    this.setClass = this.setClass.bind(this);
+    this.defineClass = this.defineClass.bind(this);
+    this.setAccTitle = this.setAccTitle.bind(this);
+    this.setAccDescription = this.setAccDescription.bind(this);
+  }
 
-// Update initial declarations
-let relations: Relation[] = [];
-let latestRequirement: Requirement = getInitialRequirement();
-let requirements = new Map<string, Requirement>();
-let latestElement: Element = getInitialElement();
-let elements = new Map<string, Element>();
-let classes = new Map<string, RequirementClass>();
+  public getDirection() {
+    return this.direction;
+  }
+  public setDirection(dir: string) {
+    this.direction = dir;
+  }
 
-// Add reset functions
-const resetLatestRequirement = () => {
-  latestRequirement = getInitialRequirement();
-};
+  private resetLatestRequirement() {
+    this.latestRequirement = this.getInitialRequirement();
+  }
 
-const resetLatestElement = () => {
-  latestElement = getInitialElement();
-};
+  private resetLatestElement() {
+    this.latestElement = this.getInitialElement();
+  }
 
-const addRequirement = (name: string, type: RequirementType) => {
-  if (!requirements.has(name)) {
-    requirements.set(name, {
-      name,
-      type,
-      requirementId: latestRequirement.requirementId,
-      text: latestRequirement.text,
-      risk: latestRequirement.risk,
-      verifyMethod: latestRequirement.verifyMethod,
+  private getInitialRequirement(): Requirement {
+    return {
+      requirementId: '',
+      text: '',
+      risk: '' as RiskLevel,
+      verifyMethod: '' as VerifyType,
+      name: '',
+      type: '' as RequirementType,
       cssStyles: [],
       classes: ['default'],
-    });
+    };
   }
-  resetLatestRequirement();
 
-  return requirements.get(name);
-};
-
-const getRequirements = () => requirements;
-
-const setNewReqId = (id: string) => {
-  if (latestRequirement !== undefined) {
-    latestRequirement.requirementId = id;
-  }
-};
-
-const setNewReqText = (text: string) => {
-  if (latestRequirement !== undefined) {
-    latestRequirement.text = text;
-  }
-};
-
-const setNewReqRisk = (risk: RiskLevel) => {
-  if (latestRequirement !== undefined) {
-    latestRequirement.risk = risk;
-  }
-};
-
-const setNewReqVerifyMethod = (verifyMethod: VerifyType) => {
-  if (latestRequirement !== undefined) {
-    latestRequirement.verifyMethod = verifyMethod;
-  }
-};
-
-const addElement = (name: string) => {
-  if (!elements.has(name)) {
-    elements.set(name, {
-      name,
-      type: latestElement.type,
-      docRef: latestElement.docRef,
+  private getInitialElement(): Element {
+    return {
+      name: '',
+      type: '',
+      docRef: '',
       cssStyles: [],
       classes: ['default'],
-    });
-    log.info('Added new element: ', name);
+    };
   }
-  resetLatestElement();
 
-  return elements.get(name);
-};
-
-const getElements = () => elements;
-
-const setNewElementType = (type: string) => {
-  if (latestElement !== undefined) {
-    latestElement.type = type;
-  }
-};
-
-const setNewElementDocRef = (docRef: string) => {
-  if (latestElement !== undefined) {
-    latestElement.docRef = docRef;
-  }
-};
-
-const addRelationship = (type: RelationshipType, src: string, dst: string) => {
-  relations.push({
-    type,
-    src,
-    dst,
-  });
-};
-
-const getRelationships = () => relations;
-
-const clear = () => {
-  relations = [];
-  resetLatestRequirement();
-  requirements = new Map();
-  resetLatestElement();
-  elements = new Map();
-  classes = new Map();
-  commonClear();
-};
-
-export const setCssStyle = function (ids: string[], styles: string[]) {
-  for (const id of ids) {
-    const node = requirements.get(id) ?? elements.get(id);
-    if (!styles || !node) {
-      return;
-    }
-    for (const s of styles) {
-      if (s.includes(',')) {
-        node.cssStyles.push(...s.split(','));
-      } else {
-        node.cssStyles.push(s);
-      }
-    }
-  }
-};
-
-export const setClass = function (ids: string[], classNames: string[]) {
-  for (const id of ids) {
-    const node = requirements.get(id) ?? elements.get(id);
-    if (node) {
-      for (const _class of classNames) {
-        node.classes.push(_class);
-        const styles = classes.get(_class)?.styles;
-        if (styles) {
-          node.cssStyles.push(...styles);
-        }
-      }
-    }
-  }
-};
-
-export const defineClass = function (ids: string[], style: string[]) {
-  for (const id of ids) {
-    let styleClass = classes.get(id);
-    if (styleClass === undefined) {
-      styleClass = { id, styles: [], textStyles: [] };
-      classes.set(id, styleClass);
-    }
-
-    if (style) {
-      style.forEach(function (s) {
-        if (/color/.exec(s)) {
-          const newStyle = s.replace('fill', 'bgFill'); // .replace('color', 'fill');
-          styleClass.textStyles.push(newStyle);
-        }
-        styleClass.styles.push(s);
+  public addRequirement(name: string, type: RequirementType) {
+    if (!this.requirements.has(name)) {
+      this.requirements.set(name, {
+        name,
+        type,
+        requirementId: this.latestRequirement.requirementId,
+        text: this.latestRequirement.text,
+        risk: this.latestRequirement.risk,
+        verifyMethod: this.latestRequirement.verifyMethod,
+        cssStyles: [],
+        classes: ['default'],
       });
     }
+    this.resetLatestRequirement();
 
-    requirements.forEach((value) => {
-      if (value.classes.includes(id)) {
-        value.cssStyles.push(...style.flatMap((s) => s.split(',')));
-      }
-    });
-    elements.forEach((value) => {
-      if (value.classes.includes(id)) {
-        value.cssStyles.push(...style.flatMap((s) => s.split(',')));
-      }
+    return this.requirements.get(name);
+  }
+
+  public getRequirements() {
+    return this.requirements;
+  }
+
+  public setNewReqId(id: string) {
+    if (this.latestRequirement !== undefined) {
+      this.latestRequirement.requirementId = id;
+    }
+  }
+
+  public setNewReqText(text: string) {
+    if (this.latestRequirement !== undefined) {
+      this.latestRequirement.text = text;
+    }
+  }
+
+  public setNewReqRisk(risk: RiskLevel) {
+    if (this.latestRequirement !== undefined) {
+      this.latestRequirement.risk = risk;
+    }
+  }
+
+  public setNewReqVerifyMethod(verifyMethod: VerifyType) {
+    if (this.latestRequirement !== undefined) {
+      this.latestRequirement.verifyMethod = verifyMethod;
+    }
+  }
+
+  public addElement(name: string) {
+    if (!this.elements.has(name)) {
+      this.elements.set(name, {
+        name,
+        type: this.latestElement.type,
+        docRef: this.latestElement.docRef,
+        cssStyles: [],
+        classes: ['default'],
+      });
+      log.info('Added new element: ', name);
+    }
+    this.resetLatestElement();
+
+    return this.elements.get(name);
+  }
+
+  public getElements() {
+    return this.elements;
+  }
+
+  public setNewElementType(type: string) {
+    if (this.latestElement !== undefined) {
+      this.latestElement.type = type;
+    }
+  }
+
+  public setNewElementDocRef(docRef: string) {
+    if (this.latestElement !== undefined) {
+      this.latestElement.docRef = docRef;
+    }
+  }
+
+  public addRelationship(type: RelationshipType, src: string, dst: string) {
+    this.relations.push({
+      type,
+      src,
+      dst,
     });
   }
-};
 
-export const getClasses = () => {
-  return classes;
-};
-
-const getData = () => {
-  const config = getConfig();
-  const nodes: Node[] = [];
-  const edges: Edge[] = [];
-  for (const requirement of requirements.values()) {
-    const node = requirement as unknown as Node;
-    node.id = requirement.name;
-    node.cssStyles = requirement.cssStyles;
-    node.cssClasses = requirement.classes.join(' ');
-    node.shape = 'requirementBox';
-    node.look = config.look;
-    nodes.push(node);
+  public getRelationships() {
+    return this.relations;
   }
 
-  for (const element of elements.values()) {
-    const node = element as unknown as Node;
-    node.shape = 'requirementBox';
-    node.look = config.look;
-    node.id = element.name;
-    node.cssStyles = element.cssStyles;
-    node.cssClasses = element.classes.join(' ');
-
-    nodes.push(node);
+  public clear() {
+    this.relations = [];
+    this.resetLatestRequirement();
+    this.requirements = new Map();
+    this.resetLatestElement();
+    this.elements = new Map();
+    this.classes = new Map();
+    commonClear();
   }
 
-  for (const relation of relations) {
-    let counter = 0;
-    const isContains = relation.type === Relationships.CONTAINS;
-    const edge: Edge = {
-      id: `${relation.src}-${relation.dst}-${counter}`,
-      start: requirements.get(relation.src)?.name ?? elements.get(relation.src)?.name,
-      end: requirements.get(relation.dst)?.name ?? elements.get(relation.dst)?.name,
-      label: `&lt;&lt;${relation.type}&gt;&gt;`,
-      classes: 'relationshipLine',
-      style: ['fill:none', isContains ? '' : 'stroke-dasharray: 10,7'],
-      labelpos: 'c',
-      thickness: 'normal',
-      type: 'normal',
-      pattern: isContains ? 'normal' : 'dashed',
-      arrowTypeEnd: isContains ? 'requirement_contains' : 'requirement_arrow',
-      look: config.look,
-    };
-
-    edges.push(edge);
-    counter++;
+  public setCssStyle(ids: string[], styles: string[]) {
+    for (const id of ids) {
+      const node = this.requirements.get(id) ?? this.elements.get(id);
+      if (!styles || !node) {
+        return;
+      }
+      for (const s of styles) {
+        if (s.includes(',')) {
+          node.cssStyles.push(...s.split(','));
+        } else {
+          node.cssStyles.push(s);
+        }
+      }
+    }
   }
 
-  return { nodes, edges, other: {}, config, direction: getDirection() };
-};
+  public setClass(ids: string[], classNames: string[]) {
+    for (const id of ids) {
+      const node = this.requirements.get(id) ?? this.elements.get(id);
+      if (node) {
+        for (const _class of classNames) {
+          node.classes.push(_class);
+          const styles = this.classes.get(_class)?.styles;
+          if (styles) {
+            node.cssStyles.push(...styles);
+          }
+        }
+      }
+    }
+  }
 
-export default {
-  Relationships,
-  RequirementType,
-  RiskLevel,
-  VerifyType,
-  getConfig: () => getConfig().requirement,
-  addRequirement,
-  getRequirements,
-  setNewReqId,
-  setNewReqText,
-  setNewReqRisk,
-  setNewReqVerifyMethod,
-  setAccTitle,
-  getAccTitle,
-  setAccDescription,
-  getAccDescription,
-  setDiagramTitle,
-  getDiagramTitle,
-  getDirection,
-  setDirection,
-  addElement,
-  getElements,
-  setNewElementType,
-  setNewElementDocRef,
-  addRelationship,
-  getRelationships,
-  clear,
-  setCssStyle,
-  setClass,
-  defineClass,
-  getClasses,
-  getData,
-};
+  public defineClass(ids: string[], style: string[]) {
+    for (const id of ids) {
+      let styleClass = this.classes.get(id);
+      if (styleClass === undefined) {
+        styleClass = { id, styles: [], textStyles: [] };
+        this.classes.set(id, styleClass);
+      }
+
+      if (style) {
+        style.forEach(function (s) {
+          if (/color/.exec(s)) {
+            const newStyle = s.replace('fill', 'bgFill'); // .replace('color', 'fill');
+            styleClass.textStyles.push(newStyle);
+          }
+          styleClass.styles.push(s);
+        });
+      }
+
+      this.requirements.forEach((value) => {
+        if (value.classes.includes(id)) {
+          value.cssStyles.push(...style.flatMap((s) => s.split(',')));
+        }
+      });
+      this.elements.forEach((value) => {
+        if (value.classes.includes(id)) {
+          value.cssStyles.push(...style.flatMap((s) => s.split(',')));
+        }
+      });
+    }
+  }
+
+  public getClasses() {
+    return this.classes;
+  }
+
+  public getData() {
+    const config = getConfig();
+    const nodes: Node[] = [];
+    const edges: Edge[] = [];
+    for (const requirement of this.requirements.values()) {
+      const node = requirement as unknown as Node;
+      node.id = requirement.name;
+      node.cssStyles = requirement.cssStyles;
+      node.cssClasses = requirement.classes.join(' ');
+      node.shape = 'requirementBox';
+      node.look = config.look;
+      nodes.push(node);
+    }
+
+    for (const element of this.elements.values()) {
+      const node = element as unknown as Node;
+      node.shape = 'requirementBox';
+      node.look = config.look;
+      node.id = element.name;
+      node.cssStyles = element.cssStyles;
+      node.cssClasses = element.classes.join(' ');
+
+      nodes.push(node);
+    }
+
+    for (const relation of this.relations) {
+      let counter = 0;
+      const isContains = relation.type === this.Relationships.CONTAINS;
+      const edge: Edge = {
+        id: `${relation.src}-${relation.dst}-${counter}`,
+        start: this.requirements.get(relation.src)?.name ?? this.elements.get(relation.src)?.name,
+        end: this.requirements.get(relation.dst)?.name ?? this.elements.get(relation.dst)?.name,
+        label: `&lt;&lt;${relation.type}&gt;&gt;`,
+        classes: 'relationshipLine',
+        style: ['fill:none', isContains ? '' : 'stroke-dasharray: 10,7'],
+        labelpos: 'c',
+        thickness: 'normal',
+        type: 'normal',
+        pattern: isContains ? 'normal' : 'dashed',
+        arrowTypeEnd: isContains ? 'requirement_contains' : 'requirement_arrow',
+        look: config.look,
+      };
+
+      edges.push(edge);
+      counter++;
+    }
+
+    return { nodes, edges, other: {}, config, direction: this.getDirection() };
+  }
+
+  public setAccTitle = setAccTitle;
+  public getAccTitle = getAccTitle;
+  public setAccDescription = setAccDescription;
+  public getAccDescription = getAccDescription;
+  public setDiagramTitle = setDiagramTitle;
+  public getDiagramTitle = getDiagramTitle;
+  public getConfig = () => getConfig().class;
+}
diff --git a/packages/mermaid/src/diagrams/requirement/requirementDiagram.ts b/packages/mermaid/src/diagrams/requirement/requirementDiagram.ts
index 619f5b052..246d91197 100644
--- a/packages/mermaid/src/diagrams/requirement/requirementDiagram.ts
+++ b/packages/mermaid/src/diagrams/requirement/requirementDiagram.ts
@@ -1,13 +1,15 @@
 import type { DiagramDefinition } from '../../diagram-api/types.js';
 // @ts-ignore: JISON doesn't support types
 import parser from './parser/requirementDiagram.jison';
-import db from './requirementDb.js';
+import { RequirementDB } from './requirementDb.js';
 import styles from './styles.js';
 import renderer from './requirementRenderer.js';
 
 export const diagram: DiagramDefinition = {
   parser,
-  db,
+  get db() {
+    return new RequirementDB();
+  },
   renderer,
   styles,
 };