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

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/**
* @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);
};
});