feat(translation): Translate pipe

demos/i18n/index.ts

@@ -3,10 +3,11 @@ import {Control, ControlGroup} from 'angular2/forms';
 
 import {IonicApp, App, Http} from 'ionic/ionic';
 
-import {Translate} from 'ionic/ionic';
+import {Translate, TranslatePipe} from 'ionic/ionic';
 
 @App({
-  templateUrl: 'main.html'
+  templateUrl: 'main.html',
+  pipes: [TranslatePipe]
 })
 class MyApp {
   constructor(app: IonicApp, trans: Translate) {
@@ -18,8 +19,8 @@ class MyApp {
     });
 
     console.log(this.trans.translate('Location'));
-    console.log(this.trans.translate('de', 'Location'));
-    this.trans.setLanguage('de');
+    console.log(this.trans.translate('Location', 'de'));
+    //this.trans.setLanguage('de');
     console.log(this.trans.translate('Location'));
 
   }

demos/i18n/main.html

@@ -1,12 +1,5 @@
-<ion-menu #menu [content]="content">
-  <ion-toolbar><ion-title>Plugins</ion-title></ion-toolbar>
+<ion-view>
   <ion-content>
-    <ion-list>
-      <button ion-item *ng-for="#p of plugins" (click)="openPage(menu, p)">
-        {{p.title}}
-      </button>
-    </ion-list>
+    Hello! What is your {{ 'Location' | translate }}
   </ion-content>
-</ion-menu>
-
-<ion-nav #content swipe-back-enabled="false" [root]="firstPage" id="myNav"></ion-nav>
+</ion-view>

ionic/ionic.ts

@@ -26,3 +26,4 @@ export * from './transitions/md-transition'
 export * from './platform/plugins'
 
 export * from './translation/translate'
+export * from './translation/translate_pipe'

ionic/translation/translate.ts

@@ -18,22 +18,18 @@ export class Translate {
     return this._transMap[lang];
   }
 
-  translate(lang, key) {
-    // If called with just one param, first is the key
-    if(typeof key === 'undefined') {
-      key = lang;
-      lang = this._language;
-    }
-
-    // If the language isn't specified, return the string passed.
-    if(!lang) {
+  translate(key, lang) {
+    // If the language isn't specified and we have no overridden one, return the string passed.
+    if(!lang && !this._language) {
       return key;
     }
 
-    let map = this.getTranslations(lang);
+    let setLanguage = lang || this._language;
+
+    let map = this.getTranslations(setLanguage);
 
     if(!map) {
-      console.warn('I18N: No translation for key', key, 'using language', this._language);
+      console.warn('I18N: No translation for key', key, 'using language', setLanguage);
       return '';
     }
     return this._getTranslation(map, key);

ionic/translation/translate_pipe.ts

@@ -0,0 +1,30 @@
+import {Injectable, Pipe, PipeTransform} from 'angular2/angular2';
+
+import {Translate} from './translate';
+
+/**
+ * The Translate pipe makes it easy to translate strings.
+ *
+ * @usage
+ * Translate using the current language or language set through Translate.setLanguage
+ * {{ 'Please enter your location' | translate }}
+ *
+ * Translate using a specific language
+ * {{ 'Please enter your location' | translate:"de" }}
+ */
+@Pipe({name: 'translate'})
+@Injectable()
+export class TranslatePipe implements PipeTransform {
+  constructor(translate: Translate) {
+    this.translate = translate;
+  }
+  transform(value, args) {
+    let lang;
+    if(args.length > 0) {
+      lang = args[0];
+    }
+    return this.translate.translate(value, lang);
+  }
+
+  supports(obj) { return true; }
+}