Select actions from the given configuration

Usage no npm install needed!

<script type="module">
  import actionSelector from '';


action-selector v1.0.2

CI codecov

Select actions from the given configuration


npm install action-selector


See the example below:

const { select } = require('action-selector')
const argv = require('minimist')(process.argv.slice(2))

const actions = {
  'action:help': () => showHelpMessage(),
  'action:version': () => showVersionNumber(),
  'action:build': () => buildSomething(),

select(actions, {
  help: || argv._[0] === 'help',
  version: argv.version || argv._[0] === 'version',
  [argv._[0]]: true,
.on('action', action => action(argv))
.on('no-action', name => console.log(`No such action: ${name}`))

With the above example, the command maps like the below:

node command.js --help    # => help action
node command.js help      # => help action
node command.js --version # => version action
node command.js version   # => version action
node command.js build     # => build action
node command.js explode   # => No such action: explode


const { select } = require('action-selector')

select(object, config)

  • @param {Object} object The object from which the selector look up the action
  • @param {Object} config The config by which the selector look up the action
  • @return {EventEmitter}

The selector look up the function in object.

The rule is:

  • Checks each key of config from the top
  • The first key which has truthy value in config is the name of the chosen action.
  • Then check action:${actionName} key in object.
  • If action:${actionName} exists in object then that is the action and emits action event with it.
  • If action:${actionName} doesn't exist in object then emits no-action event with the missing action's name.


  • 2017-06-19 v1.0.1 Support node.js v4.