async-child-process


A simple Promise-based API for working with ChildProcesses.

Usage

``sh
npm install --save async-child-process
`

$3

Waits for child to exit.

Returns a Promise that:
- will resolve {code: 0} if child exits with code 0
- with reject with an error otherwise
- error.code will be the exit code if the child exited normally
- error.signal will be the signal the child was terminated with, if any
- Note: if child emits an error, it may be the rejection reason and it may not have code or signal

Example:

`es6
import {exec} from 'child_process'
import {join} from 'async-child-process'

async function test() {
await join(exec('echo hello world'))
}
`

$3

Sends a signal to child and waits for it to exit.

Returns a Promise that:
- will resolve once child is killed
- will reject with an error if child emits one

Example:
`es6
import {exec} from 'child_process'
import {kill} from 'async-child-process'

async function test() {
const child = exec(node -e 'setTimeout(() => console.log("finally!"), 1e11)')
await kill(child)
}
`

$3

Waits for child to print something to its stdout and/or stderr. Returns a promise that:
- will resolve with the message that matched predicate or
- will reject if child exited or errored before printing a message that matched predicate

Arguments:
- child: the ChildProcess to listen to
- predicate: childPrinted will wait until child's stream(s) output a message matching the predicate
- stream: which of child's streams to listen to, omit to listen to both stdout and stderr

Example:
`es6
import {exec} from 'child_process'
import {childPrinted} from 'async-child-process'

async function test() {
const child = exec(webpack --config webpack.config.dev.js)
await childPrinted(child, /webpack built in \d+ ms/)
}
`

$3

Like exec, but returns a Promise that:
- will resolve with {stdout: string, stderr: string} from running command if it exited with code 0
- will reject with an error otherwise
- error.code will be the exit code if the child exited normally
- error.signal will be the signal the child was terminated with, if any
- Note: if child emits an error, it may be the rejection reason and it may not have code or signal

Example:
`es6
import {execAsync} from 'async-child-process'

async function test() {
const {stdout} = await execAsync('docker-compose port webapp 80')
const testUrl = stdout.trim()
}
``