Yield

Don't Start Function Until Current Callstack Ends

Install

npm install --save cjs-yield

How It Works

Call Function Normally

  say_hi();
  console.log( 'callstack ends' );

  // output
  // > Hi!
  // > callstack ends

Yield Function Call

  var _yield = require( 'cjs-yield' );

  _yield( say_hi );
  console.log( 'callstack ends' );

  // output
  // > callstack ends
  // > Hi!

Pass Yielded Function Arguments

  _yield( say_hi, 'Dr. Nick' );
  console.log( 'callstack ends' );

  // output
  // > callstack ends
  // > Hi Dr. Nick!

  _yield( say_hi, 'Archie', 'the Drells' );
  console.log( 'callstack ends' );

  // output
  // > callstack ends
  // > Hi Archie and the Drells!

  _yield( say_hi, 'Ed', 'Edd', 'Eddy' );
  console.log( 'callstack ends' );

  // output
  // > callstack ends
  // > Hi Ed, Edd and Eddy!

Gotchas

1. Yield DOES NOT work with functions that internally use this

Internally, yield uses setTimeout.apply to yield a given function, while making it easy to pass arguments to it. To make the API as simple and as pleasant as posible, setTimeout.apply uses null as its default context. This is fine unless the function use this keyword internally. Even if you avoid writing functions that use this, you can't escape it since many native JavaScript array methods like Array.push use it.

To yield a function that uses this, put the troublesome function into a function that doesn't use this and pass that new function to yield.

Eg.

  var heroes = [];
  _yield( heroes.push, 'Batman' );
  console.log( 'callstack ends' );

  // > callstack ends
  // > heroes=[]

vs

  var heroes = [];
  _yield( add_hero, 'Batman' );
  console.log( 'callstack ends' );

  // > callstack ends
  // > heroes=[ 'Batman' ]

  function add_hero( name ){
    heroes.push( name );
  }