1.0.0 • Published 9 years ago
ensure-async v1.0.0
ensure-async
Wrap an async function and ensure it calls its callback on a later tick of the event loop. Based on async#ensureAsync as module.
Install
npm install ensure-async --save
If you want to use in the browser (powered by Browserify):
bower install ensure-async --save
and later link in your HTML:
<script src="bower_components/ensure-async/dist/ensure-async.js"></script>
Usage
var ensureAsync = require('ensure-async');
function sometimesAsync(arg, callback) {
if (cache[arg]) {
return callback(null, cache[arg]); // this would be synchronous!!
} else {
doSomeIO(arg, callback); // this IO would be asynchronous
}
}
// this has a risk of stack overflows if many results are cached in a row
async.mapSeries(args, sometimesAsync, done);
// this will defer sometimesAsync's callback if necessary,
// preventing stack overflows
async.mapSeries(args, ensureAsync(sometimesAsync), done);
API
ensureAsync(fn)
Wrap an async function and ensure it calls its callback on a later tick of the event loop. If the function already calls its callback on a next tick, no extra deferral is added. This is useful for preventing stack overflows (RangeError: Maximum call stack size exceeded
) and generally keeping Zalgo contained.
Arguments
fn
- an async function, one that expects a node-style callback as its last argument
Returns a wrapped function with the exact same call signature as the function passed in.
License
MIT © Kiko Beats