diff --git a/lib/cli.ts b/lib/cli.ts
index eb65cdb..f9c4865 100644
--- a/lib/cli.ts
+++ b/lib/cli.ts
@@ -1,4 +1,8 @@
-require("es6-promise").polyfill();
+try {
+    // cackward compatibility for node v0.12
+    require("es6-promise").polyfill();
+} catch (e) {
+}
 try {
     require("typescript");
 } catch (e) {
diff --git a/lib/index.ts b/lib/index.ts
index dfdc5f2..09dd3c2 100644
--- a/lib/index.ts
+++ b/lib/index.ts
@@ -60,7 +60,7 @@ export function processFiles(files: string[], opts: Options): Promise<ResultMap>
         let content = fs.readFileSync(fileName).toString();
         return processString(fileName, content, opts);
     });
-    return Promise.all(promises).then(resultList=> {
+    return Promise.all(promises).then(resultList => {
         resultList.forEach(result => {
             resultMap[result.fileName] = result;
         });
diff --git a/npm-shrinkwrap.json b/npm-shrinkwrap.json
index 1c6224b..6e1f92e 100644
--- a/npm-shrinkwrap.json
+++ b/npm-shrinkwrap.json
@@ -386,11 +386,6 @@
       "from": "csproj2ts@0.0.6",
       "resolved": "https://registry.npmjs.org/csproj2ts/-/csproj2ts-0.0.6.tgz",
       "dependencies": {
-        "es6-promise": {
-          "version": "2.3.0",
-          "from": "es6-promise@>=2.0.1 <3.0.0",
-          "resolved": "https://registry.npmjs.org/es6-promise/-/es6-promise-2.3.0.tgz"
-        },
         "lodash": {
           "version": "3.10.1",
           "from": "lodash@>=3.3.1 <4.0.0",
@@ -528,9 +523,9 @@
       "resolved": "https://registry.npmjs.org/error-ex/-/error-ex-1.3.0.tgz"
     },
     "es6-promise": {
-      "version": "3.0.2",
-      "from": "es6-promise@3.0.2",
-      "resolved": "https://registry.npmjs.org/es6-promise/-/es6-promise-3.0.2.tgz"
+      "version": "2.3.0",
+      "from": "es6-promise@>=2.0.0 <3.0.0",
+      "resolved": "https://registry.npmjs.org/es6-promise/-/es6-promise-2.3.0.tgz"
     },
     "escallmatch": {
       "version": "1.4.2",
@@ -893,14 +888,7 @@
     "grunt-dtsm": {
       "version": "0.2.9",
       "from": "grunt-dtsm@0.2.9",
-      "resolved": "https://registry.npmjs.org/grunt-dtsm/-/grunt-dtsm-0.2.9.tgz",
-      "dependencies": {
-        "es6-promise": {
-          "version": "2.3.0",
-          "from": "es6-promise@>=2.0.0 <3.0.0",
-          "resolved": "https://registry.npmjs.org/es6-promise/-/es6-promise-2.3.0.tgz"
-        }
-      }
+      "resolved": "https://registry.npmjs.org/grunt-dtsm/-/grunt-dtsm-0.2.9.tgz"
     },
     "grunt-exec": {
       "version": "0.4.6",
diff --git a/package.json b/package.json
index d1a8cd5..410b1e6 100644
--- a/package.json
+++ b/package.json
@@ -24,7 +24,7 @@
     "url": "https://github.com/vvakame/typescript-formatter/issues"
   },
   "engines": {
-    "node": ">= 0.12.0"
+    "node": ">= 4.2.0"
   },
   "directories": {
     "example": "example",
@@ -33,7 +33,6 @@
   "dependencies": {
     "commandpost": "1.0.0",
     "editorconfig": "0.13.2",
-    "es6-promise": "3.0.2",
     "glob-expand": "0.1.0"
   },
   "peerDependencies": {
diff --git a/test/indexSpec.ts b/test/indexSpec.ts
index 6293565..43ea210 100644
--- a/test/indexSpec.ts
+++ b/test/indexSpec.ts
@@ -96,8 +96,8 @@ describe("tsfmt test", () => {
     describe("processFiles function", () => {
         var fileNames = collectFileName(fixtureDir);
         fileNames
-            .filter(fileName=> /\.ts$/.test(fileName))
-            .forEach(fileName=> {
+            .filter(fileName => /\.ts$/.test(fileName))
+            .forEach(fileName => {
                 var ignoreList = [
                     "./test/fixture/editorconfig/space/main.ts", // TypeScript ignore indentSize: 8
                     "./test/fixture/tsfmt/a/main.ts", // TypeScript ignore indentSize: 1
@@ -196,7 +196,7 @@ describe("tsfmt test", () => {
                     editorconfig: true,
                     tsfmt: true
                 })
-                .then(result=> {
+                .then(result => {
                     assert(result !== null);
                     assert(result.error === false);
                     assert(result.dest === "class Sample { getString(): string { return \"hi!\"; } }\r\n");