JS Partials

index.js

var __slice = Array.prototype.slice;

function callFirst(fn, larg) {
  return function() {
    var args = __slice.call(arguments, 0);
    
    return fn.apply(this, [larg].concat(args));
  }
}

function callLast(fn, rarg) {
  return function() {
    var args = __slice.call(arguments, 0);
    return fn.apply(this, args.concat([rarg]))
  }
}

function greet(me, you) {
  return "Hello " + you + ", this is " + me;
}

var sayHelloTo = callFirst(greet, 'Andrew');
var beGreetedBy = callLast(greet, 'Andrew');

sayHelloTo('John')
beGreetedBy('Terry')