async-once

[![NPM version][npm-image]][npm-url] [![Downloads][downloads-image]][npm-url] [![Build Status][ci-image]][ci-url] [![Coveralls Status][coveralls-image]][coveralls-url]

Guarantee a node-style async function is only executed once.

Usage

``js
var once = require('async-once');

var count = 0;

var myAsyncFunc = once(function (cb) {
count++;
cb(null, count);
});

myAsyncFunc(function (err, result) {
assert(result === 1);
});

myAsyncFunc(function (err, result) {
assert(result === 1);
});

assert(count === 1);
`

API

$3

Takes a node-style async function (fn) to ensure it's only called once. The function should accept a callback as its last parameter which is called with cb(err, result). Returns a function that can be called any number of times but will only execute once. Arguments passed to the returned function will be passed to the fn`.

License

MIT

[downloads-image]: https://img.shields.io/npm/dm/async-once.svg?style=flat-square
[npm-url]: https://www.npmjs.com/package/async-once
[npm-image]: https://img.shields.io/npm/v/async-once.svg?style=flat-square

[ci-url]: https://github.com/gulpjs/async-once/actions?query=workflow:dev
[ci-image]: https://img.shields.io/github/workflow/status/gulpjs/async-once/dev?style=flat-square

[coveralls-url]: https://coveralls.io/r/gulpjs/async-once
[coveralls-image]: https://img.shields.io/coveralls/gulpjs/async-once/master.svg?style=flat-square