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@5.9.0'
</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 || 6 || 8 || 10 || 12 || 14 || 16 || 18 || 20 || 21 with Require for modules

History

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

Backers

Code

Discover how to contribute via the CONTRIBUTING.md file.

Authors

Benjamin Lupton — Accelerating collaborative wisdom.

Maintainers

Benjamin Lupton — Accelerating collaborative wisdom.

Contributors

Finances

Donors

License

Unless stated otherwise all works are:

and licensed under:

Artistic License 2.0

Current Tags

5.9.0 ... latest (2 years ago)