Map, Filter and Reduce in JavaScript

//map() : Creates a new array by performing some operation on each array element.

let arr = [45, 23, 21];

// Array map method

let a = arr.map((value, index, array) => {

    console.log(value, index, array);

    return value + index;

});

console.log(a);

//filter() : Filters an array with values that passes a test. Creates a new array.

//Array filter method

let arr2 = [45, 23, 21, 0, 3, 5];

let a2 = arr2.filter((value) => {

    return value < 10;

});

console.log(a2);

//reduce() : Reduces an array to a single value

//Array reduce method

let arr3 = [1, 2, 3, 5, 2, 1];

let newarr3 = arr3.reduce((h1, h2) => {

    return h1 + h2;

});

console.log(newarr3);

OUTPUT:

45 0 [ 45, 23, 21 ] 23 1 [ 45, 23, 21 ] 21 2 [ 45, 23, 21 ] [ 45, 24, 23 ] [ 0, 3, 5 ] 14

JavaScript