spawnCommand


_SpawnCommand_ will run the spawn or fork methods from the child_process module, and add a promise property to the returned process instance. The promise will be resolved on process exit with an object consisting of code, stdout and stderr properties.

``
yarn add spawncommand
`

Table Of Contents

- Table Of Contents
- API
* Types
* _spawncommand.ChildProcessWithPromise
* _spawncommand.PromiseResult
* [spawn(module: string, args: string[], options?: SpawnOptions): ChildProcessWithPromise](#spawnmodule-stringargs-stringoptions-spawnoptions-childprocesswithpromise)
* [fork(module: string, args: string[], options?: ForkOptions): ChildProcessWithPromise](#forkmodule-stringargs-stringoptions-forkoptions-childprocesswithpromise)
- Copyright

API

_SpawnCommand_ can be used by importing the default spawn and named fork exports.

`js
import spawn, { fork } from 'spawncommand'
`

$3

The package's main type is _ChildProcessWithPromise_ which enriches the standard _ChildProcess_ with a promise property.

import('child_process').ChildProcess __child_process.ChildProcess__

___spawncommand.ChildProcessWithPromise__: A child process with an extra promise property.

| Name | Type | Description |
| ----------------- | ----------------------------------------------------- | ------------------------------------------ |
| __promise*__ | !Promise<!_spawncommand.PromiseResult> | A promise resolved when the process exits. |
| __spawnCommand*__ | string | The spawn arguments joined by whitespace. |

___spawncommand.PromiseResult__

| Name | Type | Description |
| ----------- | --------------- | ---------------------------------------------- |
| __stdout*__ | string | The accumulated result of the stdout stream. |
| __stderr*__ | string | The accumulated result of the stderr stream. |
| __code*__ | number | The code with which the process exited. |

$3

Spawns a command and returns a _ChildProcess_ instance with the promise property resolved on exit. The promise will be rejected if an error was encountered when trying to spawn the process.

import('child_process').SpawnOptions __child_process.SpawnOptions__

`js
import spawn from 'spawncommand'

(async () => {
const { promise } = spawn('echo', ['hello world'])
const { stderr, stdout, code } = await promise
console.log(JSON.stringify({
stderr, stdout, code,
}, null, 2))
})()
`
`json5
{
"stderr": "",
"stdout": "hello world\n",
"code": 0
}
`

The returned object is a ChildProcess and all of its properties can be accessed in the standard way.

`js
import spawnCommand from 'spawncommand'

(async () => {
const { stdout, promise } = spawnCommand('echo', ['hello world'])

stdout.pipe(process.stdout)
await promise
})()
`
`
hello world
`

$3

Forks a Node.js module and adds a promise property to the returned _ChildProcess_.

import('child_process').ForkOptions __child_process.ForkOptions__

`js
import { fork } from 'spawncommand'

(async () => {
const { promise } = fork('node_modules/.bin/alanode',
['example/spawn.js'], {
stdio: 'pipe',
})
const { stdout } = await promise
console.log(stdout)
})()
`
`json5
{
"stderr": "",
"stdout": "hello world\n",
"code": 0
}
`

The pipe option needs to be set in order to gather the output of the stderr and stdout` streams (or an array for older versions of Node.js when [this does not work][2]).

Copyright

	© Art Deco 2019	alt="Tech Nation Visa" />	Tech Nation Visa Sucks

[2]: https://github.com/nodejs/node/pull/10866