extract-opts

Extract Options & Callback

Extract the options and callback from a function's arguments easily

Usage

var log = console.log.bind(console)
var extractOptsAndCallback = require('extract-opts')

// fs.readFile(filename, [options], callback)
function readFile(filename, opts, next) {
    // Extract options and callback
    var args = extractOptsAndCallback(opts, next)
    opts = args[0]
    next = args[1]

    // Forward for simplicities sake
    require('fs').readFile(filename, opts, next)
}

// Test it
readFile('package.json', log) // works with no options
readFile('package.json', null, log) // works with null options
readFile('package.json', { next: log }) // works with just options

Customisation

Extract Options and Callback also supports a third argument. You can use this third argument to customize the completionCallbackNames property that defaults to ['next']. This is useful if your completion callback has other names besides next. Allowing you to do the following:

var log = console.log.bind(console)
function extractOptsAndCallback(opts, next, config) {
    if (config == null) config = {}
    if (config.completionCallbackNames == null)
        config.completionCallbackNames = ['next', 'complete', 'done']
    return require('extract-opts')(opts, next, config)
}

// The readFile method as before

// Test it
readFile('package.json', { next: log }) // works the standard completion callback name
readFile('package.json', { complete: log }) // works with our custom completion callback name
readFile('package.json', { done: log }) // works with our custom completion callback name

Install

npm

• Install: npm install --save extract-opts
• Import: import * as pkg from ('extract-opts')
• Require: const pkg = require('extract-opts')

jspm

<script type="module">
    import * as pkg from '//dev.jspm.io/extract-opts@5.4.1'
</script>

Editions

This package is published with the following editions:

• extract-opts aliases extract-opts/index.cjs which uses the Editions Autoloader to automatically select the correct edition for the consumer's environment
• extract-opts/source/index.js is ESNext source code for Node.js 6 || 8 || 10 || 12 || 14 || 16 || 18 || 20 || 21 with Require for modules
• extract-opts/edition-browsers/index.js is ESNext compiled for web browsers with Require for modules
• extract-opts/edition-node-4/index.js is ESNext compiled for Node.js 4 with Require for modules

History

Discover the release history by heading on over to the HISTORY.md file.

Contribute

Discover how you can contribute by heading on over to the CONTRIBUTING.md file.

Backers

Maintainers

These amazing people are maintaining this project:

• Benjamin Lupton — view contributions

Sponsors

No sponsors yet! Will you be the first?

Contributors

These amazing people have contributed code to this project:

• Benjamin Lupton — view contributions
• Matt Bierner — view contributions
• Sean Fridman — view contributions

Discover how you can contribute by heading on over to the CONTRIBUTING.md file.

License

Unless stated otherwise all works are:

• Copyright © 2013+ Bevry Pty Ltd
• Copyright © 2011+ Benjamin Lupton

and licensed under:

• Artistic License 2.0

Changelog

v5.4.1 2023 December 5

• Compatibility with eachr v7