Convert a Number into an Array in JavaScript

A number can be converted into an array of its individual digits using different JavaScript approaches.

• Convert the number to a string and process each digit.
• Extract digits using mathematical operations.
• Use built-in methods or recursion depending on the requirement.

Approach 1: Using Array.from() Method

The Array.from() method creates an array from an iterable. By converting the number to a string, each digit can be converted into a separate array element.

let num = 235345;

let arr = Array.from(String(num), Number);

console.log(arr);

[ 2, 3, 5, 3, 4, 5 ]

Approach 2: Using Mathematical Operations

In this approach, the modulo (%) operator extracts the last digit of the number, while Math.floor() removes the last digit. The extracted digits are added to the beginning of the array.

let num = 12345;
let arr = [];

while (num > 0) {
    arr.unshift(num % 10);
    num = Math.floor(num / 10);
}

console.log(arr);

[ 1, 2, 3, 4, 5 ]

Approach 3: Using for Loop

A for loop can iterate through the string representation of the number and add each digit to a new array.

const num = 12345;
const arr = [];
const str = String(num);

for (let i = 0; i < str.length; i++) {
    arr.push(Number(str[i]));
}

console.log(arr);

[ 1, 2, 3, 4, 5 ]

Approach 4: Using split() Method

The split() method splits the string representation of the number into individual characters. The map(Number) converts each character into a number.

const number = 235345;

const res = number.toString().split('').map(Number);

console.log(res);

[ 2, 3, 5, 3, 4, 5 ]

Approach 5: Using Recursion

Recursion can repeatedly remove the last digit and construct the array from the remaining digits.

function fun(num) {
    if (num === 0) {
        return [];
    }

    const dig = fun(Math.floor(num / 10));
    dig.push(num % 10);

    return dig;
}

const num = 235345;
const res = fun(num);

console.log(res);