Babel ES6 conversion script not working with npm script

I am working on NodeJS with ES6.

I have the below configuration for build in scripts in package.json

  "scripts": {
    "start": "node bin/dev",
    "test": "npm build && standard --fix && mocha test/out/**spec.js",
    "build": "babel src/server --out-dir out/server && babel test/server --out-dir out/server"
  },

But the build script is not running when I run npm build. It does not give any error. But does not convert the code to ES6.

But If I directly run the same command from console, its working.

babel src/server --out-dir out/server && babel test/server --out-dir out/server

via Shamnad P S