if (!Array.prototype.filter){
  Array.prototype.filter = function(func, thisArg) {
    'use strict';
    if ( ! ((typeof func === 'Function' || typeof func === 'function') && this) )
        throw new TypeError();

    var len = this.length >>> 0,
        res = new Array(len), // preallocate array
        t = this, c = 0, i = -1;
    if (thisArg === undefined){
      while (++i !== len){
        // checks to see if the key was set
        if (i in this){
          if (func(t[i], i, t)){
            res[c++] = t[i];
          }
        }
      }
    }
    else{
      while (++i !== len){
        // checks to see if the key was set
        if (i in this){
          if (func.call(thisArg, t[i], i, t)){
            res[c++] = t[i];
          }
        }
      }
    }

    res.length = c; // shrink down array to proper size
    return res;
  };
}

Var result = [].filter()

// [ 1, 2, 3, 7 ,4]  filter even numbers

 [ 1, 2, 3, 7 ,4].filter(number => number%2);


Array.prototype.filter = (callbackFunction, array) => {
	// callbackFunction.apply(array, this.arguments)
	const result = []
Const rsult = array.map((arrayInstance, index) => {
		Const booleanResult = callbackFunction.apply(arrayInstance);
		Final
result.push();
	}
}