Add AstDeclaration.findChildrenWithName()

octogonz · octogonz · commit 8df88d630e4a · 2019-03-24T22:28:17.000-07:00
diff --git a/apps/api-extractor/src/analyzer/AstDeclaration.ts b/apps/api-extractor/src/analyzer/AstDeclaration.ts
@@ -53,10 +53,14 @@ export class AstDeclaration {
    */
   public metadata: unknown;
 
+  // NOTE: This array becomes immutable after astSymbol.analyze() sets astSymbol.analyzed=true
   private readonly _analyzedChildren: AstDeclaration[] = [];
 
   private readonly _analyzedReferencedAstEntitiesSet: Set<AstEntity> = new Set<AstEntity>();
 
+  // Reverse lookup used by findChildrenWithName()
+  private _childrenByName: Map<string, AstDeclaration[]> | undefined = undefined;
+
   public constructor(options: IAstDeclarationOptions) {
     this.declaration = options.declaration;
     this.astSymbol = options.astSymbol;
@@ -182,6 +186,40 @@ export class AstDeclaration {
     }
   }
 
+  /**
+   * Returns the list of child declarations whose `AstSymbol.localName` matches the provided `name`.
+   *
+   * @remarks
+   * This is an efficient O(1) lookup.
+   */
+  public findChildrenWithName(name: string): ReadonlyArray<AstDeclaration> {
+    // The children property returns:
+    //
+    //    return this.astSymbol.analyzed ? this._analyzedChildren : [];
+    //
+    if (!this.astSymbol.analyzed || this._analyzedChildren.length === 0) {
+      return [];
+    }
+
+    if (this._childrenByName === undefined) {
+      // Build the lookup table
+      const childrenByName: Map<string, AstDeclaration[]> = new Map<string, AstDeclaration[]>();
+
+      for (const child of this._analyzedChildren) {
+        const childName: string = child.astSymbol.localName;
+        let array: AstDeclaration[] | undefined = childrenByName.get(childName);
+        if (array === undefined) {
+          array = [];
+          childrenByName.set(childName, array);
+        }
+        array.push(child);
+      }
+      this._childrenByName = childrenByName;
+    }
+
+    return this._childrenByName.get(name) || [];
+  }
+
   /**
    * This function determines which ts.Node kinds will generate an AstDeclaration.
    * These correspond to the definitions that we can add AEDoc to.
