Gulp.js command execution for humans.

As opposed to similar plugins or to child_process.exec(), this uses Execa which provides:

Better Windows support, including shebangs
Faster and more secure commands, since no shell is used by default
Execution of locally installed binaries
Interleaved stdout/stderr

gulp-execa adds Gulp-specific features to Execa including:

a task shortcut syntax
configurable verbosity
better errors

Commands can be executed either directly or inside a files stream. In streaming mode, unlike other libraries:

commands are run in parallel, not serially
output can be saved either in files or in variables

Example

gulpfile.js:

import gulp from 'gulp'
import { task, exec, stream } from 'gulp-execa'

export const audit = task('npm audit')

export const outdated = async () => {
  await exec('npm outdated')
}

export const sort = () =>
  gulp
    .src('*.txt')
    .pipe(stream(({ path }) => `sort ${path}`))
    .pipe(gulp.dest('sorted'))

Demo

You can try this library:

either directly in your browser.
or by executing the examples files in a terminal.

Install

npm install -D gulp-execa

This plugin requires Gulp 4.

This package is an ES module and must be loaded using an import or import() statement, not require().

Methods

task(command, [options])

Returns a Gulp task that executes command.

import { task } from 'gulp-execa'

export const audit = task('npm audit')

exec(command, [options])

Executes command. The return value is both a promise and a child_process instance.

The promise will be resolved with the command result. If the command failed, the promise will be rejected with a nice error. If the reject: false option was used, the promise will be resolved with that error instead.

import { exec } from 'gulp-execa'

export const outdated = async () => {
  await exec('npm outdated')
}

stream(function, [options])

Returns a stream that executes a command on each input file.

function must:

take a Vinyl file as argument. The most useful property is file.path but other properties are available as well.
return either:
- a command string
- an options object with a command property
- undefined

import gulp from 'gulp'
import { stream } from 'gulp-execa'

export const sort = () =>
  gulp
    .src('*.txt')
    .pipe(stream(({ path }) => `sort ${path}`))
    .pipe(gulp.dest('sorted'))

Each file in the stream will spawn a separate process. This can consume lots of resources so you should only use this method when there are no alternatives such as:

firing a command programmatically instead of spawning a child process
passing several files, a directory or a globbing pattern as arguments to the command

The verbose, stdout, stderr, all and stdio options cannot be used with this method.

Command

By default no shell interpreter (like Bash or cmd.exe) is used. This means command must be just the program and its arguments. No escaping/quoting is needed, except for significant spaces (with a backslash).

Shell features such as globbing, variables and operators (like && > ;) should not be used. All of this can be done directly in Node.js instead.

Shell interpreters are slower, less secure and less cross-platform. However, you can still opt-in to using them with the shell option.

import { writeFileStream } from 'fs'

import gulp from 'gulp'
import { task } from 'gulp-execa'

// Wrong
// export const check = task('npm audit && npm outdated')

// Correct
export const check = gulp.series(task('npm audit'), task('npm outdated'))

// Wrong
// export const install = task('npm install > log.txt')

// Correct
export const install = task('npm install', {
  stdout: writeFileStream('log.txt'),
})

Options

options is an optional object.

All Execa options can be used. Please refer to its documentation for a list of possible options.

The following options are available as well.

echo

Type: boolean
Default: true for task() and exec(), false for stream().

Whether the command should be printed on the console.

$ gulp audit
[13:09:39] Using gulpfile ~/code/gulpfile.js
[13:09:39] Starting 'audit'...
[13:09:39] [gulp-execa] npm audit
[13:09:44] Finished 'audit' after 4.96 s

verbose

Type: boolean
Default: true for task() and exec(), false for stream().

Whether both the command and its output (stdout/stderr) should be printed on the console instead of being returned in JavaScript.

$ gulp audit
[13:09:39] Using gulpfile ~/code/gulpfile.js
[13:09:39] Starting 'audit'...
[13:09:39] [gulp-execa] npm audit

                        == npm audit security report ===

found 0 vulnerabilities
 in 27282 scanned packages
[13:09:44] Finished 'audit' after 4.96 s

result

Type: string
Value: 'replace' or 'save'
Default: 'replace'

With stream(), whether the command result should:

replace the file's contents
save: be pushed to the file.execa array property

import gulp from 'gulp'
import { stream } from 'gulp-execa'
import through from 'through2'

export const task = () =>
  gulp
    .src('*.js')
    // Prints the number of lines of each file
    .pipe(stream(({ path }) => `wc -l ${path}`, { result: 'save' }))
    .pipe(
      through.obj((file, encoding, func) => {
        console.log(file.execa[0].stdout)
        func(null, file)
      }),
    )

from

Type: string
Value: 'stdout', 'stderr' or 'all'
Default: 'stdout'

Which output stream to use with result: 'replace'.

import gulp from 'gulp'
import { stream } from 'gulp-execa'
import through from 'through2'

export const task = () =>
  gulp
    .src('*.js')
    // Prints the number of lines of each file, including `stderr`
    .pipe(
      stream(({ path }) => `wc -l ${path}`, { result: 'replace', from: 'all' }),
    )
    .pipe(
      through.obj((file, encoding, func) => {
        console.log(file.contents.toString())
        func(null, file)
      }),
    )