Maybe

Promises for those afraid of commitment. Maybe can be used just like Promise.

Browser Support

IE8+, Chrome, Firefox, IOS 4+, Safari 5+, Opera

Node

npm install maybe-polyfill

Bower

bower install maybe-polyfill

Simple use

var mayb = new Maybe(function(resolve, reject) {
  // do a thing, possibly async, then…

  if (/* everything turned out fine */) {
    resolve("Stuff worked!");
  }  else {
    reject(new Error("It broke"));
  }
});

// Do something when async done
maybe.then(function() {
  ...
});

Performance

By default maybe-polyfill uses setImmediate, but falls back to setTimeout for executing asynchronously. If a browser does not support setImmediate (IE/Edge are the only browsers with setImmediate), you may see performance issues. Use a setImmediate polyfill to fix this issue. setAsap or setImmediate work well.

If you polyfill window.setImmediate or use Maybe._setImmediateFn(immedateFn) it will be used instead of window.setTimeout

npm install setasap --save

var Maybe = require('maybe-polyfill');
var setAsap = require('setasap');
Maybe._setImmediateFn(setAsap);

Unhandled Rejections

maybe-polyfill will warn you about possibly unhandled rejections. It will show a console warning if a Maybe is rejected, but no .catch is used. You can turn off this behavior by setting Maybe._setUnhandledRejectionFn(<rejectError>). If you would like to disable unhandled rejections. Use a noop like below.

Maybe._setUnhandledRejectionFn(function(rejectError) {});

Testing

npm install
npm test

License

MIT