angular/modules/@angular/common/src/pipes/i18n_select_pipe.ts
2016-06-23 11:44:05 -07:00

56 lines
1.3 KiB
TypeScript

/**
* @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 {Pipe, PipeTransform} from '@angular/core';
import {isBlank, isStringMap} from '../facade/lang';
import {InvalidPipeArgumentException} from './invalid_pipe_argument_exception';
/**
*
* Generic selector that displays the string that matches the current value.
*
* ## Usage
*
* expression | i18nSelect:mapping
*
* where `mapping` is an object that indicates the text that should be displayed
* for different values of the provided `expression`.
*
* ## Example
*
* ```
* <div>
* {{ gender | i18nSelect: inviteMap }}
* </div>
*
* class MyApp {
* gender: string = 'male';
* inviteMap: any = {
* 'male': 'Invite her.',
* 'female': 'Invite him.',
* 'other': 'Invite them.'
* }
* ...
* }
* ```
*
* @experimental
*/
@Pipe({name: 'i18nSelect', pure: true})
export class I18nSelectPipe implements PipeTransform {
transform(value: string, mapping: {[key: string]: string}): string {
if (isBlank(value)) return '';
if (!isStringMap(mapping)) {
throw new InvalidPipeArgumentException(I18nSelectPipe, mapping);
}
return mapping.hasOwnProperty(value) ? mapping[value] : '';
}
}