Array Polyfill

hi i m Rounit Singh and currently learning js from [CHAI AUR CODE ] and in todays lecture i have learned to make polyfill (a polyfill is a set of code which the developers of the software write for the methods/ functions we use with data structure that some browsers don’t support ). Some of the old version browser don’t support some of the methods due to which when we use those methods in our code our site crashes as browsers don’t support those methods in that case developer of that software write those methods on their own to engage the vast variety of the user.

polyfill which i learned in my todays class was [length , push , forEach , Filter , Map]

code for the above topics:

//creating a polyfill of length in array

//signature(how that method works) - when we use it with the array it tells the length(size) of that array

//working of the length method 
let arr = [1,2,3]
console.log(arr.length) // output - 3

//creating a polyfill of length in array

Array.prototype.lambai = function(){
    let count =0
    for(let i of this){
        count++
    }
    return count
}
console.log(arr.lambai()) // output - 3

// creating a polyfill for ForEach

//signature - it return nothing(undefine) , take input as user function , iterate over every element of the array, perform operation written inside function for every element//creating a polyfill of forEach()

//creating a polyfill of forEach()

let arr = [1,2,3]

//this is the working of foreach loop 
arr.forEach((value , index)=>{ // and it return nothing (undefined)
    console.log(value) // output - 1,2,3
})

//creating my own pollyfill
if(!Array.prototype.myforEach){
    Array.prototype.myforEach = function(myFunction){
        const originalArr = this
        for(let i =0; i<originalArr.lambai(); i++){
            myFunction(originalArr[i], i)
        }
    }

}
arr.myforEach(function(value,index){
console.log(value,index)
}) // output - [1,0]
  //           [2,1]
  //           [3,2]

// creating a polyfill of map function

//signature - return a new array , take input of a function , iterate over every element

// working of the map function : 
let arr = [1,2,3]
const result_map = arr.map(function(value){return value*2}
console.log(result_map) //output - [2,4,6]

//polyfill of map fucntion
if(!Array.prototype.myMap){
    Array.prototype.myMap = function(input_function){
        let myarr = this
        let new_arr = []
        for(let i=0; i< myarr.lambai();i++){
           const value_ = input_function(myarr[i],i)
            new_arr.push(value_)
        }
        return new_arr
    }
}

const result = arr.myMap((value)=> value*2)
console.log(result) //output - [2,4,6]

// creating polyfill for filter

//signature - return a new array , input a use function , if function return true value push the current value in the new array

//working of the filter method
let arr = [1,2,3]
const result_filter = arr.filter(function(value){return value%2 ==0}
console.log(result_filter) //output - [2]

// polyfill of the filter method 

if(!Array.prototype.myFilter){
    Array.prototype.myFilter = function(user_fucntion){
        let final_arr  = []
        for(let i =0; i < this.lambai(); i++){
            if(user_fucntion(this[i],i)){
                final_arr.push(this[i])
            }
        }

        return final_arr
    }
}

const filter_result = arr.myFilter((value)=> value%2 ==0)
console.log(filter_result) // output - [2]

// creating a polyfill of push()

//signature - take input of the value user want to push into the array

//working of the push method

let arr = [1,2,3]
arr.psuh(4)
console.log(arr) // output - [1,2,3,4]

// creating a polyfill of push()

if(!Array.prototype.mypush){
    Array.prototype.mypush = function(push_input){
        let arr_size = this.lambai()
        this[arr_size] = push_input
    }
}
arr.mypush(2)
console.log(arr) //output - [1,2,3,2]
arr.mypush(3)
console.log(arr) //output - [1,2,3,2,3]
arr.mypush(4)
console.log(arr) //output - [1,2,3,2,3,4]
arr.mypush(5)
console.log(arr) //output - [1,2,3,2,3,4,5]

// else are in the building phase and soon will be deployed …