Extract source map generation logic out of the emitter.

Jakefile.js

@@ -40,6 +40,7 @@ var compilerSources = [
     "utilities.ts",
     "binder.ts",
     "checker.ts",
+    "sourcemap.ts",
     "declarationEmitter.ts",
     "emitter.ts",
     "program.ts",
@@ -59,6 +60,7 @@ var servicesSources = [
     "utilities.ts",
     "binder.ts",
     "checker.ts",
+    "sourcemap.ts",
     "declarationEmitter.ts",
     "emitter.ts",
     "program.ts",
@@ -466,7 +468,7 @@ compileFile(servicesFile, servicesSources,[builtLocalDirectory, copyright].conca
                 var nodeDefinitionsFileContents = definitionFileContents + "\r\nexport = ts;";
                 fs.writeFileSync(nodeDefinitionsFile, nodeDefinitionsFileContents);
 
-                // Node package definition file to be distributed without the package. Created by replacing 
+                // Node package definition file to be distributed without the package. Created by replacing
                 // 'ts' namespace with '"typescript"' as a module.
                 var nodeStandaloneDefinitionsFileContents = definitionFileContents.replace(/declare (namespace|module) ts/g, 'declare module "typescript"');
                 fs.writeFileSync(nodeStandaloneDefinitionsFile, nodeStandaloneDefinitionsFileContents);
@@ -875,7 +877,7 @@ var tslintRulesOutFiles = tslintRules.map(function(p) {
 desc("Compiles tslint rules to js");
 task("build-rules", tslintRulesOutFiles);
 tslintRulesFiles.forEach(function(ruleFile, i) {
-    compileFile(tslintRulesOutFiles[i], [ruleFile], [ruleFile], [], /*useBuiltCompiler*/ false, /*noOutFile*/ true, /*generateDeclarations*/ false, path.join(builtLocalDirectory, "tslint")); 
+    compileFile(tslintRulesOutFiles[i], [ruleFile], [ruleFile], [], /*useBuiltCompiler*/ false, /*noOutFile*/ true, /*generateDeclarations*/ false, path.join(builtLocalDirectory, "tslint"));
 });
 
 function getLinterOptions() {
@@ -937,7 +939,7 @@ function lintWatchFile(filename) {
         if (event !== "change") {
             return;
         }
-     
+
         if (!lintSemaphores[filename]) {
             lintSemaphores[filename] = true;
             lintFileAsync(getLinterOptions(), filename, function(err, result) {

src/compiler/core.ts

@@ -356,6 +356,33 @@ namespace ts {
         return result;
     }
 
+    /**
+     * Reduce the properties of a map.
+     *
+     * @param map The map to reduce
+     * @param callback An aggregation function that is called for each entry in the map
+     * @param initial The initial value for the reduction.
+     */
+    export function reduceProperties<T, U>(map: Map<T>, callback: (aggregate: U, value: T, key: string) => U, initial: U): U {
+        let result = initial;
+        if (map) {
+            for (const key in map) {
+                if (hasProperty(map, key)) {
+                    result = callback(result, map[key], String(key));
+                }
+            }
+        }
+
+        return result;
+    }
+
+    /**
+     * Tests whether a value is an array.
+     */
+    export function isArray(value: any): value is any[] {
+        return Array.isArray ? Array.isArray(value) : value instanceof Array;
+    }
+
     export function memoize<T>(callback: () => T): () => T {
         let value: T;
         return () => {