angular2/ts/src/core/linker/exceptions.ts

Angular 2 - a web framework for modern web apps

import {BaseException, WrappedException} from "angular2/src/facade/exceptions";

/**
 * An error thrown if application changes model breaking the top-down data flow.
 *
 * This exception is only thrown in dev mode.
 *
 * <!-- TODO: Add a link once the dev mode option is configurable -->
 *
 * ### Example
 *
 * ```typescript
 * @Component({
 *   selector: 'parent',
 *   template: `
 *     <child [prop]="parentProp"></child>
 *   `,
 *   directives: [forwardRef(() => Child)]
 * })
 * class Parent {
 *   parentProp = "init";
 * }
 *
 * @Directive({selector: 'child', inputs: ['prop']})
 * class Child {
 *   constructor(public parent: Parent) {}
 *
 *   set prop(v) {
 *     // this updates the parent property, which is disallowed during change detection
 *     // this will result in ExpressionChangedAfterItHasBeenCheckedException
 *     this.parent.parentProp = "updated";
 *   }
 * }
 * ```
 */
export class ExpressionChangedAfterItHasBeenCheckedException extends BaseException {
  constructor(oldValue: any, currValue: any, context: any) {
    super(`Expression has changed after it was checked. ` +
          `Previous value: '${oldValue}'. Current value: '${currValue}'`);
  }
}

/**
 * Thrown when an exception was raised during view creation, change detection or destruction.
 *
 * This error wraps the original exception to attach additional contextual information that can
 * be useful for debugging.
 */
export class ViewWrappedException extends WrappedException {
  constructor(originalException: any, originalStack: any, context: any) {
    super(`Error in ${context.source}`, originalException, originalStack, context);
  }
}

/**
 * Thrown when a destroyed view is used.
 *
 * This error indicates a bug in the framework.
 *
 * This is an internal Angular error.
 */
export class ViewDestroyedException extends BaseException {
  constructor(details: string) { super(`Attempt to use a destroyed view: ${details}`); }
}