diff --git a/package.json b/package.json
index d44ab4c..d5b8911 100644
--- a/package.json
+++ b/package.json
@@ -14,11 +14,12 @@
   "scripts": {
     "build": "tsc -d",
     "build:w": "tsc -d -w",
-    "release": "del ./dist && npm run build",
+    "release": "del dist && npm run build",
     "lint": "tslint ./src/**/*.ts ./test/**/*.test.ts",
     "check": "npm run build && npm run lint",
     "test": "npm run check && npm run test-local",
     "test-local": "egg-bin test --ts",
+    "prepublish": "npm run release",
     "cov": "npm run check && egg-bin cov --ts"
   },
   "keywords": [
diff --git a/src/register.ts b/src/register.ts
index 42a68c6..6d672b8 100644
--- a/src/register.ts
+++ b/src/register.ts
@@ -22,10 +22,17 @@ function register(watch: boolean) {
     // write jsconfig if the project is wrote by js
     util.writeJsConfig(cwd);
   } else {
+    const tsNodeMode = util.deepGet(util.getPkgInfo(cwd), 'egg.typescript') ||
+      process.argv.includes('--ts') ||
+      process.argv.includes('--typescript') ||
+      process.env.EGG_TYPESCRIPT === 'true';
+
     // no need to clean in js project
     // clean local js file at first.
     // because egg-loader cannot load the same property name to egg.
-    util.cleanJs(cwd);
+    if (tsNodeMode) {
+      util.cleanJs(cwd);
+    }
   }
 
   if (watch) {
diff --git a/src/utils.ts b/src/utils.ts
index 0dd5eb2..a9b9069 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -269,9 +269,7 @@ export function cleanJs(cwd: string) {
     .sync([ '**/*.ts', '**/*.tsx', '!**/*.d.ts', '!**/node_modules' ], { cwd })
     .forEach(f => {
       const jf = removeSameNameJs(path.resolve(cwd, f));
-      if (jf) {
-        fileList.push(jf);
-      }
+      if (jf) fileList.push(path.relative(cwd, jf));
     });
 
   if (fileList.length) {