write your own map function javascript code example

Example 1: how the map function works javascript

const array = [2, 5, 9];
let squares = array.map((num) => num * num);

console.log(array); // [2, 5, 9]
console.log(squares); // [4, 25, 81]

Example 2: how to create my own filter in js

// filter takes an array and function as argumentfunction 
filter(arr, filterFunc) {
  const filterArr = []; // empty array        
  // loop though array    
  for(let i=0;i<arr.length;i++) {        
    const result = filterFunc(arr[i], i, arr);        
    // push the current element if result is true        
    if(result)             
      filterArr.push(arr[i]);     
  }    
  return filterArr;
}