singlefile

singlefile
==========

Ensures that your async function runs to completion before it is executed again

``javascript
// example of loading and caching a config file
var singlefile = require("singlefile");
var _config = null;
var getConfig = singlefile(function(cb) {
console.log("getConfig called");
if (_config !== null) {
return cb(null, _config);
}

// fake delay demonstrating disk/network read for config file
setTimeout(function() {
console.log("Setting config file");
_config = {awesome: true};
cb(null, _config);
}, 1000);
});

// let's use it
getConfig(function(err, config) {
console.log("got config 1");
});
// another call happening at the same time
getConfig(function(err, config) {
console.log("got config 2");
});

/**
* LOG OUTPUT
* getConfig called
* Setting config file
* got config 1
* getConfig called
* got config 2
*/
``