]
07-21-2023, 03:02 PM
## npm 2 and newer ##
It's possible to [pass args to `npm run`](
`npm run <command> [-- <args>]`
Note the `--` separator, used to separate the params passed to `npm` command itself, and the params passed to your script.
With the example `package.json`:
```json
"scripts": {
"grunt": "grunt",
"server": "node server.js"
}
```
here's how to pass the params to those scripts:
```sh
npm run grunt -- task:target // invokes `grunt task:target`
npm run server -- --port=1337 // invokes `node server.js --port=1337`
```
_Note_: **If your param does not start with `-` or `--`, then having an explicit `--` separator is not needed; but it's better to do it anyway for clarity.**
```sh
npm run grunt task:target // invokes `grunt task:target`
```
Note below the difference in behavior (`test.js` has `console.log(process.argv)`): the params which start with `-` or `--` _are passed to `npm` and not to the script_, and are silently swallowed there.
```sh
$ npm run test foobar
['C:\\Program Files\\nodejs\\node.exe', 'C:\\git\\myrepo\\test.js', 'foobar']
$ npm run test -foobar
['C:\\Program Files\\nodejs\\node.exe', 'C:\\git\\myrepo\\test.js']
$ npm run test --foobar
['C:\\Program Files\\nodejs\\node.exe', 'C:\\git\\myrepo\\test.js']
$ npm run test -- foobar
['C:\\Program Files\\nodejs\\node.exe', 'C:\\git\\myrepo\\test.js', 'foobar']
$ npm run test -- -foobar
['C:\\Program Files\\nodejs\\node.exe', 'C:\\git\\myrepo\\test.js', '-foobar']
$ npm run test -- --foobar
['C:\\Program Files\\nodejs\\node.exe', 'C:\\git\\myrepo\\test.js', '--foobar']
```
The difference is clearer when you use a param _actually used by npm_:
```sh
$ npm test --help // this is disguised `npm --help test`
npm test [-- <args>]
aliases: tst, t
```
To get the parameter value, [see this question](
It's possible to [pass args to `npm run`](
[To see links please register here]
) since npm 2 (2014). The syntax is as follows:`npm run <command> [-- <args>]`
Note the `--` separator, used to separate the params passed to `npm` command itself, and the params passed to your script.
With the example `package.json`:
```json
"scripts": {
"grunt": "grunt",
"server": "node server.js"
}
```
here's how to pass the params to those scripts:
```sh
npm run grunt -- task:target // invokes `grunt task:target`
npm run server -- --port=1337 // invokes `node server.js --port=1337`
```
_Note_: **If your param does not start with `-` or `--`, then having an explicit `--` separator is not needed; but it's better to do it anyway for clarity.**
```sh
npm run grunt task:target // invokes `grunt task:target`
```
Note below the difference in behavior (`test.js` has `console.log(process.argv)`): the params which start with `-` or `--` _are passed to `npm` and not to the script_, and are silently swallowed there.
```sh
$ npm run test foobar
['C:\\Program Files\\nodejs\\node.exe', 'C:\\git\\myrepo\\test.js', 'foobar']
$ npm run test -foobar
['C:\\Program Files\\nodejs\\node.exe', 'C:\\git\\myrepo\\test.js']
$ npm run test --foobar
['C:\\Program Files\\nodejs\\node.exe', 'C:\\git\\myrepo\\test.js']
$ npm run test -- foobar
['C:\\Program Files\\nodejs\\node.exe', 'C:\\git\\myrepo\\test.js', 'foobar']
$ npm run test -- -foobar
['C:\\Program Files\\nodejs\\node.exe', 'C:\\git\\myrepo\\test.js', '-foobar']
$ npm run test -- --foobar
['C:\\Program Files\\nodejs\\node.exe', 'C:\\git\\myrepo\\test.js', '--foobar']
```
The difference is clearer when you use a param _actually used by npm_:
```sh
$ npm test --help // this is disguised `npm --help test`
npm test [-- <args>]
aliases: tst, t
```
To get the parameter value, [see this question](
[To see links please register here]
). For reading named parameters, it's probably best to use a parsing library like [yargs]([To see links please register here]
) or [minimist]([To see links please register here]
); nodejs exposes `process.argv` globally, containing command line parameter values, but this is a low-level API (whitespace-separated array of strings, as provided by the operating system to the node executable).