JavaScript Array Polyfills

This project contains custom implementations of important JavaScript array methods to understand how they work internally.

Implemented Methods

• myForEach()
• myMap()
• myFilter()
• myReduce()

Purpose

The goal of this project is to strengthen core JavaScript fundamentals by recreating built-in array methods using basic loops and logic.

🧠 Method Signatures

myForEach

• Takes a callback function
• Executes the function for each element
• Returns undefined

myMap

• Takes a callback function
• Returns a new array
• Each element is transformed using the callback

myFilter

• Takes a callback function
• Returns a new array
• Includes elements where callback returns true

myReduce

• Takes a callback function and an optional initial value
• Returns a single accumulated value

Example

const arr = [1, 2, 3, 4, 5];

const doubled = arr.myMap((num) => num * 2);
console.log(doubled);

const even = arr.myFilter((num) => num % 2 === 0);
console.log(even);

const sum = arr.myReduce((acc, curr) => acc + curr, 0);
console.log(sum);