Package Exports

extract-opts

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (extract-opts) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

Extract Options & Callback

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

Install

npm

Install: npm install --save extract-opts
Require: require('extract-opts')

jspm

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

Editions

This package is published with the following editions:

extract-opts aliases extract-opts/source/index.js
extract-opts/source/index.js is esnext source code with require for modules
extract-opts/edition-browsers/index.js is esnext compiled for browsers with require for modules

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