refactor(): use const and let instead of var

modules/@angular/facade/src/collection.ts

@@ -15,11 +15,11 @@ export class StringMapWrapper {
   static merge<V>(m1: {[key: string]: V}, m2: {[key: string]: V}): {[key: string]: V} {
     const m: {[key: string]: V} = {};
 
-    for (let k of Object.keys(m1)) {
+    for (const k of Object.keys(m1)) {
       m[k] = m1[k];
     }
 
-    for (let k of Object.keys(m2)) {
+    for (const k of Object.keys(m2)) {
       m[k] = m2[k];
     }
 
@@ -99,8 +99,8 @@ export function areIterablesEqual(
   const iterator2 = b[getSymbolIterator()]();
 
   while (true) {
-    let item1 = iterator1.next();
-    let item2 = iterator2.next();
+    const item1 = iterator1.next();
+    const item2 = iterator2.next();
     if (item1.done && item2.done) return true;
     if (item1.done || item2.done) return false;
     if (!comparator(item1.value, item2.value)) return false;

modules/@angular/facade/src/intl.ts

@@ -23,7 +23,7 @@ export class NumberFormatter {
         currency?: string,
         currencyAsSymbol?: boolean
       } = {}): string {
-    let options: Intl.NumberFormatOptions = {
+    const options: Intl.NumberFormatOptions = {
       minimumIntegerDigits,
       minimumFractionDigits,
       maximumFractionDigits,
@@ -180,7 +180,7 @@ function datePartGetterFactory(ret: Intl.DateTimeFormatOptions): DateFormatterFn
 const DATE_FORMATTER_CACHE = new Map<string, string[]>();
 
 function dateFormatter(format: string, date: Date, locale: string): string {
-  let fn = PATTERN_ALIASES[format];
+  const fn = PATTERN_ALIASES[format];
 
   if (fn) return fn(date, locale);
 
@@ -206,7 +206,7 @@ function dateFormatter(format: string, date: Date, locale: string): string {
   }
 
   return parts.reduce((text, part) => {
-    let fn = DATE_FORMATS[part];
+    const fn = DATE_FORMATS[part];
     return text + (fn ? fn(date, locale) : partToTime(part));
   }, '');
 }

modules/@angular/facade/src/lang.ts

@@ -35,7 +35,7 @@ declare var WorkerGlobalScope: any /** TODO #9100 */;
 // the global "global" var for now.
 declare var global: any /** TODO #9100 */;
 
-var globalScope: BrowserNodeGlobal;
+let globalScope: BrowserNodeGlobal;
 if (typeof window === 'undefined') {
   if (typeof WorkerGlobalScope !== 'undefined' && self instanceof WorkerGlobalScope) {
     // TODO: Replace any with WorkerGlobalScope from lib.webworker.d.ts #3492
@@ -154,7 +154,7 @@ export function setValueOnPath(global: any, path: string, value: any) {
 }
 
 // When Symbol.iterator doesn't exist, retrieves the key used in es6-shim
-declare let Symbol: any;
+declare const Symbol: any;
 let _symbolIterator: any = null;
 export function getSymbolIterator(): string|symbol {
   if (!_symbolIterator) {
@@ -164,7 +164,7 @@ export function getSymbolIterator(): string|symbol {
       // es6-shim specific logic
       const keys = Object.getOwnPropertyNames(Map.prototype);
       for (let i = 0; i < keys.length; ++i) {
-        let key = keys[i];
+        const key = keys[i];
         if (key !== 'entries' && key !== 'size' &&
             (Map as any).prototype[key] === Map.prototype['entries']) {
           _symbolIterator = key;