surfingtonio/exec-series

Run commands in order

exec-series

A Node module to run commands in order

const execSeries = require('exec-series');

execSeries(['echo "foo"', 'echo "bar"'], (err, stdouts, stderrs) => {
  if (err) {
    throw err;
  }

  console.log(stdouts); // yields: ['foo\n', 'bar\n']
  console.log(stderrs); // yields: ['', '']
});

On Linux, you can do almost the same thing with && operator like below:

const {exec} = require('child_process');

exec('echo "foo" && echo "bar"', (err, stdout, stderr) => {
  //...
});

However, some environments, such as Windows PowerShell, don't support && operator. This module helps you to create a cross-platform Node program.

Installation

Use npm.

npm install exec-series

API

const execSeries = require('exec-series');

execSeries(commands [, options, callback])

commands: Array of String (the commands to run)
options: Object (child_process.exec options with maxBuffer defaulting to 10 MB)
callback: Function

It sequentially runs the commands using child_process.exec. If the first command has finished successfully, the second command will run, and so on.

After the last command has finished, it runs the callback function.

When one of the commands fails, it immediately calls the callback function and the rest of the commands won't be run.

callback(error, stdoutArray, stderrArray)

error: Error if one of the commands fails, otherwise undefined
stdoutArray: Array of String (stdout of the commands)
stderrArray: Array of String (stderr of the commands)

execSeries([
  'mkdir foo',
  'echo bar',
  'exit 200',
  'mkdir baz'
], (err, stdouts, stderrs) => {
  err.code; //=> 200
  stdouts; //=> ['', 'bar\n', '']
  stderrs; //=> ['', '', '']
  
  fs.statSync('foo').isDirectory; //=> true
  fs.statSync('baz'); // throw an error
});

Callback function is optional.

execSeries(['mkdir foo', 'mkdir bar']);

setTimeout(() => {
  fs.statSync('foo').isDirectory(); //=> true
  fs.statSync('bar').isDirectory(); //=> true
}, 1000);

License

Copyright (c) 2014 - 2016 Shinnosuke Watanabe

Licensed under the MIT License.