Javascript Array myInject(callback)

Array.prototype.myInject = function(callback) {
  var sum = this[0];
  for(var i = 1; i < this.length; i++) {
    sum = callback(sum, this[i]);//from   w  w  w.  ja  va 2 s  .  co m
  }
  return sum;
};

var callback = function(sum, value) {
  return sum += value;
};

Array.prototype.myInject = function(callback) {
  let acc = this[0];
  const remArr = this.slice(1, this.length);

  remArr.myEach((el) => {//from w  w  w. jav  a  2s .c  o m
    acc = callback(acc, el);
  });
  return acc;
};

console.log([1,2,3,4].myInject((a, b) => { return a + b; }));

Array.prototype.myInject = function (callback) {
  var result = this[0];
  this.slice(1).myEach(function (el) {
    result = callback(result, el);/*  w  w w.j a  v  a 2 s.co m*/
  });
  return result;
}

var c = a.myInject(function (accum, el) {
  return accum + el;
});
console.log(c);