How array methods work internally => Map || Filter || Reduce

Map

We discovered the power of map, which enables us to create a new array by applying a transformation to each element of an existing array. By understanding the internal workings of, we gained insights into how it functions its magic behind the scenes

var map = function(arr, fn) {
    let n=arr.length;
    let arr2=[];
    for(let i=0;i<n;i++){
        arr2.push(fn(arr[i],i));
    }
    return arr2;

};

Filter

The enchantment of filter captivated us as we learned how to extract specific elements from an array based on certain conditions. By exploring the inner mechanics of filter, we demystified how it selectively handpicks elements.

var filter = function(arr, fn) {
    let n=arr.length;
    let arr2=[];
    for(let i=0;i<n;i++){
      if(fn(arr[i],i))
        arr2.push(arr[i]);
    }
    return arr2;

};

uses of filter ||how to use filter ||where to use filter

Reduce

We ventured into the realm of reduce, where we learned to elegantly accumulate an array into a single value using a combination of elements and a callback function. By peering into the internal mechanisms of reduce, we uncovered its ability to perform powerful aggregations.

var reduce = function(nums, fn, init) {
    for(let i=0;i<nums.length;i++){
        init=fn(init,nums[i]);
    }
    return init;
};