feat(core): add the find method to QueryList

modules/@angular/core/src/linker/query_list.ts

@@ -57,6 +57,12 @@ export class QueryList<T>/* implements Iterable<T> */ {
     return this._results.filter(fn);
   }
 
+  /**
+   * See
+   * [Array.find](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/find)
+   */
+  find(fn: (item: T, index: number, array: T[]) => boolean): T { return this._results.find(fn); }
+
   /**
    * See
    * [Array.reduce](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/reduce)

modules/@angular/core/test/linker/query_list_spec.ts

@@ -70,6 +70,16 @@ export function main() {
       expect(queryList.filter((x: string, i: number) => i == 0)).toEqual(['one']);
     });
 
+    it('should support find', () => {
+      queryList.reset(['one', 'two']);
+      expect(queryList.find((x: string) => x == 'two')).toEqual('two');
+    });
+
+    it('should support find with index', () => {
+      queryList.reset(['one', 'two']);
+      expect(queryList.find((x: string, i: number) => i == 1)).toEqual('two');
+    });
+
     it('should support reduce', () => {
       queryList.reset(['one', 'two']);
       expect(queryList.reduce((a: string, x: string) => a + x, 'start:')).toEqual('start:onetwo');

tools/public_api_guard/core/index.d.ts

@@ -697,6 +697,7 @@ export declare class QueryList<T> {
     last: T;
     length: number;
     filter(fn: (item: T, index: number, array: T[]) => boolean): T[];
+    find(fn: (item: T, index: number, array: T[]) => boolean): T;
     forEach(fn: (item: T, index: number, array: T[]) => void): void;
     map<U>(fn: (item: T, index: number, array: T[]) => U): U[];
     notifyOnChanges(): void;