Nodejs Utililty Methods Array Filter

Array.prototype.filter = function(predicate) {
  var filtered_array = [];
  this.forEach(function (element, i) {
    if (predicate(element)) filtered_array.push(element);
  });
  return filtered_array;

Array.prototype.filter = function(predicateFunction) {
  var results = [];
  this.forEach(function(itemInArray) {
    if (predicateFunction(itemInArray)) {
    results.push(itemInArray);
  });
  return results;
};
...

Array.prototype.filter = function(predicateFunction) {
  var results = [];
  this.forEach(function(itemInArray) {
    if(predicateFunction(itemInArray) == true)
      results.push(itemInArray);
  });
  return results;
};

Array.prototype.filter = function(predicateFunction){
  var result = [];
  this.forEach(function(item){
    if(predicateFunction(item)) {
      result.push(item);
  })
  return result;
Array.prototype.map = function(predicateFunction){
  var result = [];
  this.forEach(function(item){
    result.push(predicateFunction(item));
  })
  return result;
var a = [1,2,3,4,5,6,7,8,9];
a.map(function(x){
  return x*2;
}).filter(function(x){
  if(x > 4) return true;
})

var result = ['A','B','C','D','E','F'].filter(function(x) { 
  return x > 'C'
});
console.log(result);
var outcome = JSON.stringify(result);
console.log(outcome);
var testOutCome = outcome === '["D","E","F"]';
console.log(testOutCome);

Array.prototype.filter = function(predicateFunction) {
  var results = [];
  this.forEach(function(itemInArray) {
    if (predicateFunction(itemInArray)) {
    results.push(itemInArray);
  });
  return results;
};
...

Array.prototype.filter = function(predicateFunction) {
  var results = [];
  this.forEach(itemInArray => {
    if(predicateFunction(itemInArray)) {
       results.push(itemInArray);
  });
  return results;
};
...

Array.prototype.filter = function(predicateFunction) {
  var results = [];
  this.forEach(function(itemInArray) {
    if (predicateFunction(itemInArray)) {
    results.push(itemInArray);
  });
  return results;
};
...

Array.prototype.filter = function(predicateFunction) {
  var results = [];
  this.forEach(function(item) {
    if (predicateFunction(item)) {
      results.push(item);
  });
  return results;

Array.prototype.filter = function(search, func) {
  var results = [];
  for(var i = 0; i < this.length; i++) {
    if(func(search, this[i]))
       results.push(this[i]);
  return results;