diff --git a/Brocfile-dart.js b/Brocfile-dart.js
index 3bc9d4d33a..f2f220b5aa 100644
--- a/Brocfile-dart.js
+++ b/Brocfile-dart.js
@@ -6,9 +6,9 @@ var path = require('path');
 
 // Transpile everything in 'modules'...
 var modulesTree = new Funnel('modules', {
-  include: ['**/*.js', '**/*.ts', '**/*.dart'], // .dart file available means don't translate.
+  include: ['**/*.js', '**/*.ts', '**/*.dart'],  // .dart file available means don't translate.
   exclude: ['rtts_assert/**/*'],  // ... except for the rtts_asserts (don't apply to Dart).
-  destDir: '/',  // Remove the 'modules' prefix.
+  destDir: '/',                   // Remove the 'modules' prefix.
 });
 
 // Transpile to dart.
diff --git a/gulpfile.js b/gulpfile.js
index e0463d0e19..8801d1908b 100644
--- a/gulpfile.js
+++ b/gulpfile.js
@@ -504,9 +504,22 @@ gulp.task('build/format.dart', rundartpackage(gulp, gulpPlugins, {
   args: CONFIG.formatDart.args
 }));
 
+function doCheckFormat() {
+  return gulp.src(['Brocfile*.js', 'modules/**/*.ts', 'tools/**/*.ts', '!**/typings/**/*.d.ts'])
+    .pipe(format.checkFormat('file'));
+}
+
 gulp.task('check-format', function() {
-  return gulp.src(['Brocfile*.js', 'modules/**/*.ts', '!**/typings/**/*.d.ts'])
-      .pipe(format.checkFormat('file'));
+  return doCheckFormat().on('warning', function(e) {
+    console.log("NOTE: this will be promoted to an ERROR in the continuous build");
+  });
+});
+
+gulp.task('enforce-format', function() {
+  return doCheckFormat().on('warning', function(e) {
+    console.log("ERROR: Some files need formatting");
+    process.exit(1);
+  });
 });
 
 // ------------
@@ -752,6 +765,7 @@ gulp.task('build.js.dev', function(done) {
   runSequence(
     'broccoli.js.dev',
     'build/checkCircularDependencies',
+    'check-format',
     done
   );
 });
diff --git a/scripts/ci/build_js.sh b/scripts/ci/build_js.sh
index 5198cc870d..63c14b1a2e 100755
--- a/scripts/ci/build_js.sh
+++ b/scripts/ci/build_js.sh
@@ -8,4 +8,4 @@ SCRIPT_DIR=$(dirname $0)
 source $SCRIPT_DIR/env_dart.sh
 cd $SCRIPT_DIR/../..
 
-./node_modules/.bin/gulp build.js docs
+./node_modules/.bin/gulp enforce-format build.js docs
diff --git a/tools/broccoli/broccoli-ts2dart.ts b/tools/broccoli/broccoli-ts2dart.ts
index 70fed135d2..28e098deaa 100644
--- a/tools/broccoli/broccoli-ts2dart.ts
+++ b/tools/broccoli/broccoli-ts2dart.ts
@@ -9,7 +9,7 @@ import path = require('path');
 import ts2dart = require('ts2dart');
 
 type Set = {
-  [s:string]: boolean
+  [s: string]: boolean
 };
 
 class TypeScriptToDartTranspiler extends Writer {
diff --git a/tools/broccoli/broccoli-writer.d.ts b/tools/broccoli/broccoli-writer.d.ts
index 1505e4745d..ee52f3437f 100644
--- a/tools/broccoli/broccoli-writer.d.ts
+++ b/tools/broccoli/broccoli-writer.d.ts
@@ -1,8 +1,6 @@
 /// <reference path="../typings/es6-promise/es6-promise.d.ts" />
 
 
-declare class Writer {
-  write(readTree: (tree) => Promise<string>, destDir: string): Promise<any>;
-}
+declare class Writer { write(readTree: (tree) => Promise<string>, destDir: string): Promise<any>; }
 
 export = Writer;
diff --git a/tools/broccoli/traceur/index.ts b/tools/broccoli/traceur/index.ts
index 5992fb21ed..1b2764054c 100644
--- a/tools/broccoli/traceur/index.ts
+++ b/tools/broccoli/traceur/index.ts
@@ -37,7 +37,7 @@ class TraceurFilter extends Writer {
                 // TODO: we should fix the sourceMappingURL written by Traceur instead of overriding
                 // (but we might switch to typescript first)
                 var mapFilepath = filepath.replace(/\.\w+$/, '') + this.destSourceMapExtension;
-                result.js = result.js + `\n//# sourceMappingURL=./${path.basename(mapFilepath)}`;
+                result.js = result.js + '\n  //# sourceMappingURL=./' + path.basename(mapFilepath);
 
                 var destFilepath = filepath.replace(/\.\w+$/, this.destExtension);
                 var destFile = path.join(destDir, destFilepath);
diff --git a/tools/broccoli/ts2dart.d.ts b/tools/broccoli/ts2dart.d.ts
index 5b93f4cc60..3dfc6c2778 100644
--- a/tools/broccoli/ts2dart.d.ts
+++ b/tools/broccoli/ts2dart.d.ts
@@ -8,7 +8,7 @@ export interface TranspilerOptions {
   basePath?: string;
 }
 
-export class Transpiler{
+export class Transpiler {
   constructor(options: TranspilerOptions);
   transpile(fileNames: string[], outdir?: string);
 }
diff --git a/tools/broccoli/typescript/index.ts b/tools/broccoli/typescript/index.ts
index bb01e178ee..fb2579f09f 100644
--- a/tools/broccoli/typescript/index.ts
+++ b/tools/broccoli/typescript/index.ts
@@ -22,34 +22,34 @@ class TSCompiler extends Writer {
     }
     options.target = (<any>ts).ScriptTarget[options.target];
     return readTree(this.inputTree)
-      .then(srcDir => {
-        var files = walkSync(srcDir)
-          .filter(filepath => path.extname(filepath).toLowerCase() === '.ts')
-          .map(filepath => path.resolve(srcDir, filepath));
+        .then(srcDir => {
+          var files = walkSync(srcDir)
+                          .filter(filepath => path.extname(filepath).toLowerCase() === '.ts')
+                          .map(filepath => path.resolve(srcDir, filepath));
 
-        if (files.length > 0) {
-          var program = ts.createProgram(files, options);
-          var emitResult = program.emit();
+          if (files.length > 0) {
+            var program = ts.createProgram(files, options);
+            var emitResult = program.emit();
 
-          var allDiagnostics = ts.getPreEmitDiagnostics(program).concat(emitResult.diagnostics);
+            var allDiagnostics = ts.getPreEmitDiagnostics(program).concat(emitResult.diagnostics);
 
-          var errMsg = '';
-          allDiagnostics.forEach(diagnostic => {
-            var message = ts.flattenDiagnosticMessageText(diagnostic.messageText, '\n');
-            if (!diagnostic.file) {
-              errMsg += `\n${message}`;
-              return;
+            var errMsg = '';
+            allDiagnostics.forEach(diagnostic => {
+              var message = ts.flattenDiagnosticMessageText(diagnostic.messageText, '\n');
+              if (!diagnostic.file) {
+                errMsg += `\n${message}`;
+                return;
+              }
+              var {line, character} =
+                  diagnostic.file.getLineAndCharacterOfPosition(diagnostic.start);
+              errMsg += `\n${diagnostic.file.fileName} (${line + 1},${character + 1}): ${message}`;
+            });
+
+            if (emitResult.emitSkipped) {
+              throw new Error(errMsg);
             }
-            var {line, character} =
-              diagnostic.file.getLineAndCharacterOfPosition(diagnostic.start);
-            errMsg += `\n${diagnostic.file.fileName} (${line + 1},${character + 1}): ${message}`;
-          });
-
-          if (emitResult.emitSkipped) {
-            throw new Error(errMsg);
           }
-        }
-      });
+        });
   }
 }
 module.exports = TSCompiler;