npm start and test same time code example

Example 1: npm concurrently

// The tool is written in Node.js, but you can use it to run any commands.
npm install -g concurrently

// or if you are using it from npm scripts:
npm install concurrently --save

// Remember to surround separate commands with quotes:
concurrently "yarn run script1"   "yarn run script2"   "yarn run script3"

// In package.json, escape quotes:
"start": "concurrently \"command1 arg\" \"command2 arg\""

Example 2: package json scripts multiple commands

"start": "webpack && node server/server.js"