IE8 Array.prototype.splice.apply test

index.js

(function() {
  var _Array_slice_ = Array.prototype['slice'];
  var _Array_splice_ = Array.prototype.splice;
  
  if( Function.prototype.bind === void 0 ) Function.prototype.bind = function (context) {
  	var args = _Array_slice_.call(arguments, 1), self = this;
		return function (){ return self.apply(context, args.concat(_Array_slice_.call(arguments, 0))); };
	};
  
  function makeArray(l) {
      var a = [];
      while (l--) {
          a.unshift(l)
      }
      return a
  }
  
  
  Array.prototype.splice = function(start, deleteCount) {
      var result
          , args = _Array_slice_.call(arguments, 2)
          , addElementsCount = args.length
      ;
  
      if(!arguments.length) {
          return [];
      }
  
      if(start === void 0) { // default
          start = 0;
      }
      if(deleteCount === void 0) { // default
          deleteCount = this.length - start;
      }
  
      if(addElementsCount > 0) {
          if(deleteCount <= 0) {
              if(start == this.length) { // tiny optimisation #1
                  this.push.apply(this, args);
                  return [];
              }
  
              if(start == 0) { // tiny optimisation #2
                  this.unshift.apply(this, args);
                  return [];
              }
          }
  
          // Array.prototype.splice implementation
          result = _Array_slice_.call(this, start, start + deleteCount);// delete part
          args.push.apply(args, _Array_slice_.call(this, start + deleteCount, this.length));// right part
          args.unshift.apply(args, _Array_slice_.call(this, 0, start));// left part
  
          // delete all items from this array and replace it to 'left part' + _Array_slice_.call(arguments, 2) + 'right part'
          args.unshift(0, this.length);
  
          _Array_splice_.apply(this, args);
  
          return result;
      }
  
      return _Array_splice_.call(this, start, deleteCount);
  }
  
  var array = []
      , lengthBefore
  ;
  
  array.splice.bind(array, 0, 0).apply(null, makeArray(20));
  array.splice.bind(array, 0, 0).apply(null, makeArray(26));
  
  array.splice.apply(array, [5, 0, "XXX"]); // add one element
  
  return array.join(",") == "0,1,2,3,4,XXX,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19";
})();