refactor(core): cleanup code with side-effects which was preventing tree-shaking (#30580)

PR Close #30580

packages/core/src/linker/query_list.ts

@@ -12,6 +12,9 @@ import {EventEmitter} from '../event_emitter';
 import {flatten} from '../util/array_utils';
 import {getSymbolIterator} from '../util/symbol';
 
+function symbolIterator<T>(this: QueryList<T>): Iterator<T> {
+  return ((this as any as{_results: Array<T>})._results as any)[getSymbolIterator()]();
+}
 
 /**
  * An unmodifiable list of items that Angular keeps up to date when the state
@@ -50,6 +53,16 @@ export class QueryList<T>/* implements Iterable<T> */ {
   // TODO(issue/24571): remove '!'.
   readonly last !: T;
 
+  constructor() {
+    // This function should be declared on the prototype, but doing so there will cause the class
+    // declaration to have side-effects and become not tree-shakable. For this reason we do it in
+    // the constructor.
+    // [getSymbolIterator()](): Iterator<T> { ... }
+    const symbol = getSymbolIterator();
+    const proto = QueryList.prototype as any;
+    if (!proto[symbol]) proto[symbol] = symbolIterator;
+  }
+
   /**
    * See
    * [Array.map](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map)
@@ -99,8 +112,6 @@ export class QueryList<T>/* implements Iterable<T> */ {
    */
   toArray(): T[] { return this._results.slice(); }
 
-  [getSymbolIterator()](): Iterator<T> { return (this._results as any)[getSymbolIterator()](); }
-
   toString(): string { return this._results.toString(); }
 
   /**

packages/core/src/util/global.ts

@@ -15,20 +15,16 @@ declare var global: any /** TODO #9100 */;
 // Not yet available in TypeScript: https://github.com/Microsoft/TypeScript/pull/29332
 declare var globalThis: any /** TODO #9100 */;
 
-function getGlobal(): any {
-  const __globalThis = typeof globalThis !== 'undefined' && globalThis;
-  const __window = typeof window !== 'undefined' && window;
-  const __self = typeof self !== 'undefined' && typeof WorkerGlobalScope !== 'undefined' &&
-      self instanceof WorkerGlobalScope && self;
-  const __global = typeof global !== 'undefined' && global;
+const __globalThis = typeof globalThis !== 'undefined' && globalThis;
+const __window = typeof window !== 'undefined' && window;
+const __self = typeof self !== 'undefined' && typeof WorkerGlobalScope !== 'undefined' &&
+    self instanceof WorkerGlobalScope && self;
+const __global = typeof global !== 'undefined' && global;
 
-  // Always use __globalThis if available, which is the spec-defined global variable across all
-  // environments, then fallback to __global first, because in Node tests both __global and
-  // __window may be defined and _global should be __global in that case.
-  return __globalThis || __global || __window || __self;
-}
-
-const _global = getGlobal();
+// Always use __globalThis if available, which is the spec-defined global variable across all
+// environments, then fallback to __global first, because in Node tests both __global and
+// __window may be defined and _global should be __global in that case.
+const _global = __globalThis || __global || __window || __self;
 
 /**
  * Attention: whenever providing a new value, be sure to add an

packages/core/src/util/ng_i18n_closure_mode.ts

@@ -19,9 +19,12 @@ if (typeof ngI18nClosureMode === 'undefined') {
   // These property accesses can be ignored because ngI18nClosureMode will be set to false
   // when optimizing code and the whole if statement will be dropped.
   // Make sure to refer to ngI18nClosureMode as ['ngI18nClosureMode'] for closure.
-  // tslint:disable-next-line:no-toplevel-property-access
-  global['ngI18nClosureMode'] =
-      // TODO(FW-1250): validate that this actually, you know, works.
-      // tslint:disable-next-line:no-toplevel-property-access
-      typeof goog !== 'undefined' && typeof goog.getMsg === 'function';
+  // NOTE: we need to have it in IIFE so that the tree-shaker is happy.
+  (function() {
+    // tslint:disable-next-line:no-toplevel-property-access
+    global['ngI18nClosureMode'] =
+        // TODO(FW-1250): validate that this actually, you know, works.
+        // tslint:disable-next-line:no-toplevel-property-access
+        typeof goog !== 'undefined' && typeof goog.getMsg === 'function';
+  })();
 }