refactor(i18n): move message and id into a separate file

modules/angular2/src/facade/lang.dart

@@ -1,6 +1,6 @@
 library angular.core.facade.lang;
 
-export 'dart:core' show Type, RegExp, print, DateTime;
+export 'dart:core' show Type, RegExp, print, DateTime, Uri;
 import 'dart:math' as math;
 import 'dart:convert' as convert;
 import 'dart:async' show Future, Zone;
@@ -376,3 +376,7 @@ num bitWiseAnd(List values) {
   var val = values.reduce((num a, num b) => (a as int) & (b as int));
   return val as num;
 }
+
+String escape(String s) {
+  return Uri.encodeComponent(s);
+}

modules/angular2/src/facade/lang.ts

@@ -18,6 +18,7 @@ export interface BrowserNodeGlobal {
   clearTimeout: Function;
   setInterval: Function;
   clearInterval: Function;
+  encodeURI: Function;
 }
 
 // TODO(jteplitz602): Load WorkerGlobalScope from lib.webworker.d.ts file #3492
@@ -473,3 +474,7 @@ export function bitWiseOr(values: number[]): number {
 export function bitWiseAnd(values: number[]): number {
   return values.reduce((a, b) => { return a & b; });
 }
+
+export function escape(s: string): string {
+  return _global.encodeURI(s);
+}

modules/angular2/src/i18n/message.ts

@@ -0,0 +1,21 @@
+import {isPresent, escape} from 'angular2/src/facade/lang';
+
+/**
+ * A message extracted from a template.
+ *
+ * The identity of a message is comprised of `content` and `meaning`.
+ *
+ * `description` is additional information provided to the translator.
+ */
+export class Message {
+  constructor(public content: string, public meaning: string, public description: string) {}
+}
+
+/**
+ * Computes the id of a message
+ */
+export function id(m: Message): string {
+  let meaning = isPresent(m.meaning) ? m.meaning : "";
+  let content = isPresent(m.content) ? m.content : "";
+  return escape(`$ng|${meaning}|${content}`);
+}

modules/angular2/src/i18n/message_extractor.ts

@@ -13,21 +13,11 @@ import {isPresent, isBlank} from 'angular2/src/facade/lang';
 import {StringMapWrapper} from 'angular2/src/facade/collection';
 import {Parser} from 'angular2/src/core/change_detection/parser/parser';
 import {Interpolation} from 'angular2/src/core/change_detection/parser/ast';
+import {Message, id} from './message';
 
 const I18N_ATTR = "i18n";
 const I18N_ATTR_PREFIX = "i18n-";
 
-/**
- * A message extracted from a template.
- *
- * The identity of a message is comprised of `content` and `meaning`.
- *
- * `description` is additional information provided to the translator.
- */
-export class Message {
-  constructor(public content: string, public meaning: string, public description: string) {}
-}
-
 /**
  * All messages extracted from a template.
  */
@@ -56,9 +46,8 @@ export class I18nExtractionError extends ParseError {
 export function removeDuplicates(messages: Message[]): Message[] {
   let uniq: {[key: string]: Message} = {};
   messages.forEach(m => {
-    let key = `$ng__${m.meaning}__|${m.content}`;
-    if (!StringMapWrapper.contains(uniq, key)) {
-      uniq[key] = m;
+    if (!StringMapWrapper.contains(uniq, id(m))) {
+      uniq[id(m)] = m;
     }
   });
   return StringMapWrapper.values(uniq);