child-process-ext

What is child-process-ext?

The child-process-ext package is a Node.js module that extends the core 'child_process' module with additional functionality and convenience methods. It simplifies working with child processes in Node.js by providing enhanced features for spawning, executing, and managing child processes.

What are child-process-ext's main functionalities?

Spawn with Promises

This feature allows you to spawn a child process and work with it using promises, making it easier to handle the asynchronous nature of child process execution. The example shows how to list the contents of the '/usr' directory.

const { spawn } = require('child-process-ext');

async function runCommand() {
  try {
    const result = await spawn('ls', ['-lh', '/usr']);
    console.log(`stdout: ${result.stdout}`);
  } catch (error) {
    console.error(`Error: ${error.message}`);
  }
}

runCommand();

Execute with Enhanced Output Handling

This feature simplifies executing a command and directly handling its output. It enhances the default 'exec' by providing a more straightforward way to access stdout and stderr. The example demonstrates checking the Node.js version installed.

const { exec } = require('child-process-ext');

async function executeCommand() {
  try {
    const { stdout, stderr } = await exec('node -v');
    console.log(`Node Version: ${stdout}`);
  } catch (error) {
    console.error(`Error: ${stderr}`);
  }
}

executeCommand();

Other packages similar to child-process-ext

execa

Execa is a popular npm package that provides a better interface for executing child processes. It supports both promise and async/await syntax, similar to child-process-ext, but with additional features like automatic escaping of arguments and more detailed process result information.

cross-spawn

Cross-spawn is another npm package that aims to solve cross-platform issues when using child_process.spawn(). While child-process-ext enhances functionality with promises and better output handling, cross-spawn focuses on ensuring consistent behavior of spawned processes across different operating systems.

README

child-process-ext

Node.js child_process extensions

Installation

npm install child-process-ext

API

spawn(command[, args[, options]])

Cross system compliant spawn (backed by cross-spawn).

Works exactly same way as node's spawn with difference that promise is returned that resolves once process exits.

Following properties are exposed on return promise:

• child - child process
• stdout - stdout stream (decorated so it can also be used as promise)
• stderr - stderr stream (decorated so it can also be used as promise)
• std - Merged stdout & stderr stream (decorated so it can also be used as promise)
• stdoutBuffer - Buffer that exposes so far written stdout
• stderrBuffer - Buffer that exposes so far written stderrr
• stdBuffer - Buffer that exposes so far written std

Promise resolves with object with three properties:

• code - Exit code of a child proces
• signal - Signal that terminated the process
• stdoutBuffer - Buffer containing gathered stdout content
• stderrBuffer - Buffer containing gathered stderr content
• stdBuffer - Buffer containing gathered stderr content

If process exits with non zero code, then promise is rejected with an error exposing same properties as above

Non standard options

split bool (default: false)

Whether stdout data should be split by lines. If set to true, then stdout and stderr on promise expose mappers of original stdout and stderr that emit each line with distinct data event

shouldCloseStdin bool (default: false)

Whether stdin should be closed. Applicable for spawned processes where stdin is set to other than 'inherit' mode, and underlying processes is reading from stdin. Not providing any stdin output, may produce stall if process logic waits for an input. See: get-stdin#13 for more information

Tests

npm test

Changelog

3.0.2 (2023-08-22)

Bug Fixes

• Fix handling of just stderr being observable (cf390ff)