2

In almost all of the docs I've come across so far, most of the time I have seen the start and the dev script being used for a similar kind of functionality. following are 2 examples:

1.

  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "start": "node index",
    "dev": "nodemon index" 
  },

  "scripts": {
    "dev": "webpack-dev-server --inline --progress --config build/webpack.dev.conf.js",
    "start": "npm run dev",

So, please help me in understanding, what exactly is the difference between the two in package.json file used for NodeJs. Under what circumstances does mentioning the 2 at the same time make sense.

P.S: I'm new to javascript and node.js. Hence please forgive in case of a silly mistake. Thanks in advance :)

rajarshi
  • 31
  • 1
  • 3

1 Answers1

2

Start is a script handled by default by npm. You can use it without the keyword run: npm start

dev is a custom script, the name has no significance fr npm. You need to use the keyword run:

# npm run <script name>
npm run dev

documentation for start: https://docs.npmjs.com/cli/v6/commands/npm-start

documentation for run-script: https://docs.npmjs.com/cli/v6/commands/npm-run-script

In other words, start will override the default npm command. By default, npm will run node index.js on start. The start script always exists even if you don't declare it. That is not the case for dev.

Bassochette
  • 166
  • 1
  • 1
  • 13
  • I know this part, 'npm start' works exactly like 'npm run start', but 'npm dev' will not work, this is a difference in how the commands should be executed. But I was expecting more in terms of functionality. like for test script, we can mention mocha, but we'll not put mocha in start or dev, right? Like that, is there some kind of difference between start and dev too? Hope I am clear now. – rajarshi Dec 13 '20 at 08:28
  • `start` and `test` are default scripts in npm. They are the only script that work this way. Every other script will need to use the run keyword. It would make very little sense to put a mocha command in the start BUT nothing can stop you from doing it. `dev` only exist if you create it. – Bassochette Dec 13 '20 at 08:33