Posted onFeb 9, 2023

Javascript most asked polyfills

ForEach Polyfill:

Array.prototype.forEachPoly = function(cb){    for(let i = 0; i < this.length; i++){        cb(this[i], i, this);    }}

Map Polyfill:

Array.prototype.mapPoly = function(cb){    let newArr = [];    for(let i=0; i<this.length; i++){        newArr.push(cb(this[i], i, this));    }    return newArr;}

Filter Polyfill:

Array.prototype.filterPoly = function(cb){    let newArr = [];    for(let i=0; i<this.length; i++){        if(cb(this[i], i, this)){            newArr.push(this[i]);        }    }    return newArr;}

Reduce Polyfill:

Array.prototype.reducePoly = function(cb, optionalInitilizer){    console.log(optionalInitilizer);    let acc, i;    if(optionalInitilizer !== undefined){        acc = optionalInitilizer;        i=0    }else{        acc = this[0];        i=1;    }    for(i; i<this.length; i++){        acc = cb(acc, this[i],i,this)    }    return acc;}

Array.prototype.reducePoly2 = function(cb, initializer){    let acc = initializer;    for(let i=0; i<this.length; i++){        acc = acc ? cb(acc, this[i], i, this) : this[0];    }    return acc;}

Call Polyfill:

Function.prototype.callPoly = function(context={}, ...args){    context.func = this;    context.func(...args);}

Apply Polyfill:

Function.prototype.applyPoly = function(context={}, args){    context.func = this;    context.func(...args);}

Bind Polyfill:

Function.prototype.bindPoly = function(context={}, ...args){    let reqFunc = this;    return function(...newArgs){        context.func = reqFunc;        context.func(...args, ...newArgs);    }}