one-time

Call the supplied function exactly one time. This prevents double callback execution. This module can be used on both node and browsers using browserify. No magical ES5/6 methods used unlike the once module does.

Installation

npm install one-time

Usage

Simply supply the function with the function that should only be called one time:

var one = require('one-time');

function load(file, fn) {
  fn = one(fn);

  eventemitter.once('load', fn);
  eventemitter.once('error', fn);

  // do stuff
  eventemitter.emit('error', new Error('Failed to load, but still finished'));
  eventemitter.emit('load');
}

function example(fn) {
  fn = one(fn);

  fn();
  fn('also receives all arguments');
  fn('it returns the same value') === 'bar';
  fn('never');
  fn('gonna');
  fn('give');
  fn('you');
  fn('up');
}

example(function () { 
  return 'bar'
});

Why not once?

The main reason is that once cannot be used in a browser environment unless it's ES5 compatible. For a module as simple as this I find that unacceptable. In addition to that it super heavy on the dependency cite. So it's totally not suitable to be used in client side applications.

License

MIT