my implementation of the array reduce

MyReduce.js

Array.prototype.myReduce = function(fn, initialValue) {
  let accValue = [];
  let currentIndex = 0;
  if (this.length === 0) 
    return initialValue;
    
  accValue[currentIndex] = fn(initialValue, this[0]);
  for(let i = 1; i < this.length; i++) {
    accValue[i] = fn(accValue[i-1], this[i]);
    currentIndex = i;
  }
  return accValue[currentIndex];
};