Implement Custom Array.filter

JavaScript

Technical Specification

Implement a custom filter function called myFilter that works similarly to Array.prototype.filter.

Input/Output Samples

Input:[1,2,3,4].myFilter(x => x % 2 === 0)

Output:[2,4]

Optimal Logic Path

Array.prototype.myFilter = function (callback) {
  const result = [];
  for (let i = 0; i < this.length; i++) {
    if (Object.prototype.hasOwnProperty.call(this, i)) {
      if (callback(this[i], i, this)) {
        result.push(this[i]);
      }
    }
  }
  return result;
};

Architectural Deep-Dive

Similar to map, but we only store elements whose callback result is truthy.