build: move zone.js to angular repo (#30962)

PR Close #30962

packages/zone.js/lib/common/to-string.ts

@@ -0,0 +1,57 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+import {zoneSymbol} from './utils';
+
+// override Function.prototype.toString to make zone.js patched function
+// look like native function
+Zone.__load_patch('toString', (global: any) => {
+  // patch Func.prototype.toString to let them look like native
+  const originalFunctionToString = Function.prototype.toString;
+
+  const ORIGINAL_DELEGATE_SYMBOL = zoneSymbol('OriginalDelegate');
+  const PROMISE_SYMBOL = zoneSymbol('Promise');
+  const ERROR_SYMBOL = zoneSymbol('Error');
+  const newFunctionToString = function toString() {
+    if (typeof this === 'function') {
+      const originalDelegate = this[ORIGINAL_DELEGATE_SYMBOL];
+      if (originalDelegate) {
+        if (typeof originalDelegate === 'function') {
+          return originalFunctionToString.call(originalDelegate);
+        } else {
+          return Object.prototype.toString.call(originalDelegate);
+        }
+      }
+      if (this === Promise) {
+        const nativePromise = global[PROMISE_SYMBOL];
+        if (nativePromise) {
+          return originalFunctionToString.call(nativePromise);
+        }
+      }
+      if (this === Error) {
+        const nativeError = global[ERROR_SYMBOL];
+        if (nativeError) {
+          return originalFunctionToString.call(nativeError);
+        }
+      }
+    }
+    return originalFunctionToString.call(this);
+  };
+  (newFunctionToString as any)[ORIGINAL_DELEGATE_SYMBOL] = originalFunctionToString;
+  Function.prototype.toString = newFunctionToString;
+
+
+  // patch Object.prototype.toString to let them look like native
+  const originalObjectToString = Object.prototype.toString;
+  const PROMISE_OBJECT_TO_STRING = '[object Promise]';
+  Object.prototype.toString = function() {
+    if (this instanceof Promise) {
+      return PROMISE_OBJECT_TO_STRING;
+    }
+    return originalObjectToString.call(this);
+  };
+});