Favor use of ES2015 instead of ES6

src/services/tsconfig.json

@@ -27,12 +27,12 @@
         "../compiler/transformers/jsx.ts",
         "../compiler/transformers/es2017.ts",
         "../compiler/transformers/es2016.ts",
-        "../compiler/transformers/es6.ts",
+        "../compiler/transformers/es2015.ts",
         "../compiler/transformers/generators.ts",
         "../compiler/transformers/destructuring.ts",
         "../compiler/transformers/module/module.ts",
         "../compiler/transformers/module/system.ts",
-        "../compiler/transformers/module/es6.ts",
+        "../compiler/transformers/module/es2015.ts",
         "../compiler/transformer.ts",
         "../compiler/comments.ts",
         "../compiler/sourcemap.ts",

src/services/utilities.ts

@@ -1339,7 +1339,7 @@ namespace ts {
         const options: TranspileOptions = {
             fileName: "config.js",
             compilerOptions: {
-                target: ScriptTarget.ES6,
+                target: ScriptTarget.ES2015,
                 removeComments: true
             },
             reportDiagnostics: true