angular-cn/packages/core/src/error_handler.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 {ERROR_ORIGINAL_ERROR, getDebugContext, getOriginalError} from './errors';
/**
* @whatItDoes Provides a hook for centralized exception handling.
*
* @description
*
* The default implementation of `ErrorHandler` prints error messages to the `console`. To
* intercept error handling, write a custom exception handler that replaces this default as
* appropriate for your app.
*
* ### Example
*
* ```
* class MyErrorHandler implements ErrorHandler {
* handleError(error) {
* // do something with the exception
* }
* }
*
* @NgModule({
* providers: [{provide: ErrorHandler, useClass: MyErrorHandler}]
* })
* class MyModule {}
* ```
*
* @stable
*/
export class ErrorHandler {
/**
* @internal
*/
_console: Console = console;
/**
* @internal
*/
rethrowError: boolean;
constructor(rethrowError: boolean = true) { this.rethrowError = rethrowError; }
handleError(error: any): void {
this._console.error(`EXCEPTION: ${this._extractMessage(error)}`);
if (error instanceof Error) {
const originalError = this._findOriginalError(error);
const originalStack = this._findOriginalStack(error);
const context = this._findContext(error);
if (originalError) {
this._console.error(`ORIGINAL EXCEPTION: ${this._extractMessage(originalError)}`);
}
if (originalStack) {
this._console.error('ORIGINAL STACKTRACE:');
this._console.error(originalStack);
}
if (context) {
this._console.error('ERROR CONTEXT:');
this._console.error(context);
}
}
// We rethrow exceptions, so operations like 'bootstrap' will result in an error
// when an error happens. If we do not rethrow, bootstrap will always succeed.
if (this.rethrowError) throw error;
}
/** @internal */
_extractMessage(error: any): string {
return error instanceof Error ? error.message : error.toString();
}
/** @internal */
_findContext(error: any): any {
if (error) {
return getDebugContext(error) ? getDebugContext(error) :
this._findContext(getOriginalError(error));
}
return null;
}
/** @internal */
_findOriginalError(error: Error): any {
let e = getOriginalError(error);
while (e && getOriginalError(e)) {
e = getOriginalError(e);
}
return e;
}
/** @internal */
_findOriginalStack(error: Error): string {
let e: any = error;
let stack: string = e.stack;
while (e instanceof Error && getOriginalError(e)) {
e = getOriginalError(e);
if (e instanceof Error && e.stack) {
stack = e.stack;
}
}
return stack;
}
}
export function wrappedError(message: string, originalError: any): Error {
const msg =
`${message} caused by: ${originalError instanceof Error ? originalError.message: originalError }`;
const error = Error(msg);
(error as any)[ERROR_ORIGINAL_ERROR] = originalError;
return error;
}