Split a Number into an Array in JavaScript

# Split a Number into an Array in JavaScript

To split a number into an array:

1. Use the String() constructor to convert the number to a string.
2. Use the Array.from() method to convert the string to an array of digits.
3. Use the map() method to convert each string in the array to a number.

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const number = 1234;

const arrOfDigits = Array.from(String(number), Number);
console.log(arrOfDigits); // 👉️ [1, 2, 3, 4]

The first argument we passed to the Array.from() method is an iterable object that we want to convert to an array.

We had to convert the number to a string because numbers are not iterable.

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// 👇️ ['1', '2', '3', '4']
console.log(Array.from(String(1234)));

At this point we have an array of strings. We used the second parameter of the Array.from() method to convert each string to a number.

The second parameter the method takes is an Array.map() function.

The function gets called with each element in the array. We want to convert each element to a number, so we make use of the Number() constructor.

# Using the Array.map() method manually instead

Here is an equivalent example that explicitly uses the Array.map() method.

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const number = 1234;

// 👇️ ['1', '2', '3', '4']
const arrOfStr = Array.from(String(number));

const arrOfNum = arrOfStr.map(str => Number(str));
console.log(arrOfNum); // 👉️ [1, 2, 3, 4]

The function we passed to the Array.map() method gets called with each string in the array.

On each iteration, we convert the current element to a number and return the result.

Alternatively, you can use the String.split() method.

# Split a number into an Array using String.split()

This is a three-step process:

1. Use the String() constructor to convert the number to a string.
2. Call the split() method on the string to get an array of strings.
3. Call the map() method on the array to convert each string to a number.

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const number = 1234;

const arr = String(number)
  .split('')
  .map(str => Number(str));

console.log(arr); // 👉️ [1, 2, 3, 4]

We used the String() constructor to convert the number to a string and used the String.split() method.

The method splits a string into an array based on the provided separator.

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const number = 1234;

// 👇️ ['1', '2', '3' ,'4']
console.log(String(number).split(''));

Lastly, we used the map() method to convert each string to a number.

We could have also passed the Number() constructor directly to the map() method to achieve the same result.

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const number = 1234;

const arr = String(number).split('').map(Number);

console.log(arr); // 👉️ [1, 2, 3, 4]

You can imagine that the Number() constructor gets called with each element of the array, then converts the value to a number and returns the result.

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

// 👇️ [ 1, 2, 3, 4 ]
console.log(arr.map(Number));

// 👇️ [ 1, 2, 3, 4 ]
console.log(arr.map(element => Number(element)));

Note that this approach is a bit more implicit and a general rule of thumb is that being explicit makes your code more readable.

If you have to split a number into an array often, define a reusable function.

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function splitNumber(num) {
  return String(num)
    .split('')
    .map(str => Number(str));
}

console.log(splitNumber(1234)); // 👉️ [ 1, 2, 3, 4 ]
console.log(splitNumber(123)); // 👉️ [ 1, 2, 3 ]
console.log(splitNumber(12)); // 👉️ [ 1, 2 ]
console.log(splitNumber(1)); // 👉️ [ 1 ]

The splitNumber() function takes a number as a parameter and splits the number into an array.

# Additional Resources

You can learn more about the related topics by checking out the following tutorials:

• Split a String on Capital Letters using JavaScript
• Split a String and get First or Last Array Element in JS
• Split on the Last Occurrence of a String in JavaScript
• Split a String removing any Empty Elements in JavaScript
• Split a String at a specific Index using JavaScript
• How to Split a String by Newline in JavaScript
• How to Split a String by a Regex in JavaScript
• Split a String with multiple Separators using JavaScript
• How to Split a string by Spaces in JavaScript
• Split a String only on the First Occurrence of a Character
• Split a String by Special Characters in JavaScript
• Split a String every N characters in JavaScript