refactor: Add type annotations and optimize redundant set loop

packages/mermaid/src/diagrams/class/classDb.ts

@@ -36,7 +36,8 @@ let classCounter = 0;
 let namespaces = new Map<string, NamespaceNode>();
 let namespaceCounter = 0;
 
-let functions: any[] = [];
+// eslint-disable-next-line @typescript-eslint/no-unsafe-function-type
+let functions: Function[] = [];
 
 const sanitizeText = (txt: string) => common.sanitizeText(txt, getConfig());
 
@@ -125,12 +126,12 @@ export const lookUpDomId = function (_id: string): string {
 
 export const clear = function () {
   relations = [];
-  classes = new Map();
+  classes = new Map<string, ClassNode>();
   notes = new Map<string, ClassNote>();
   interfaces = [];
   functions = [];
   functions.push(setupToolTips);
-  namespaces = new Map();
+  namespaces = new Map<string, NamespaceNode>();
   namespaceCounter = 0;
   direction = 'TB';
   commonClear();
@@ -602,9 +603,7 @@ export const getData = () => {
   const edges: Edge[] = [];
   const config = getConfig();
 
-  for (const namespaceKey of namespaces.keys()) {
-    const namespace = namespaces.get(namespaceKey);
-    if (namespace) {
+  for (const namespace of namespaces.values()) {
     const node: Node = {
       id: namespace.id,
       label: namespace.id,
@@ -617,17 +616,13 @@ export const getData = () => {
     };
     nodes.push(node);
   }
-  }
 
-  for (const classKey of classes.keys()) {
-    const classNode = classes.get(classKey);
-    if (classNode) {
+  for (const classNode of classes.values()) {
     const node = classNode as unknown as Node;
     node.parentId = classNode.parent;
     node.look = config.look;
     nodes.push(node);
   }
-  }
 
   for (const note of notes.values()) {
     const noteNode: Node = {