JavaScript How to Convert String to Array Easily

Use the split() method to convert a string to an array in JavaScript, for example: const arr = str.split(''); splits the string into an array of characters.

Examples

Input"hello"

Output["h", "e", "l", "l", "o"]

Input"apple,banana,orange"

Output["apple", "banana", "orange"]

Input""

Output[]

How to Think About It

To convert a string to an array, think about how you want to split the string: by each character or by a specific separator like a comma. The split() method breaks the string into parts based on the separator you give it, returning an array of those parts.

Algorithm

1

Get the input string.

2

Choose the separator to split the string (empty string for characters, or a specific character like comma).

3

Use the split method with the chosen separator on the string.

4

Return the resulting array.

Code

javascript

const str1 = "hello";
const arr1 = str1.split('');
console.log(arr1);

const str2 = "apple,banana,orange";
const arr2 = str2.split(',');
console.log(arr2);

Output

[ 'h', 'e', 'l', 'l', 'o' ]
[ 'apple', 'banana', 'orange' ]

Dry Run

Let's trace converting "apple,banana,orange" to an array using split(',')

1

Input string

"apple,banana,orange"

2

Split by comma

Call split(',') on the string

3

Resulting array

["apple", "banana", "orange"]

Iteration	Current Part
1	apple
2	banana
3	orange

Why This Works

Step 1: Using split() method

The split() method divides the string into pieces wherever it finds the separator you give it.

Step 2: Separator choice

If you use an empty string '' as separator, it splits into single characters; if you use a comma ',', it splits at commas.

Step 3: Returns an array

The method returns a new array containing all the parts after splitting.

Alternative Approaches

Array.from()

javascript

const str = "hello";
const arr = Array.from(str);
console.log(arr);

Creates an array from the string characters; simple and readable for character arrays.

Spread operator

javascript

const str = "hello";
const arr = [...str];
console.log(arr);

Uses spread syntax to unpack string characters into an array; concise and modern.

Complexity: O(n) time, O(n) space

Time Complexity

The split() method scans the entire string once, so time grows linearly with string length.

Space Complexity

It creates a new array holding all parts, so space used is proportional to the number of parts.

Which Approach is Fastest?

split(''), Array.from(), and spread operator all run in linear time; split() is best for splitting by separators, others are simpler for characters.

Approach	Time	Space	Best For
split(separator)	O(n)	O(n)	Splitting by any separator
Array.from()	O(n)	O(n)	Converting string to array of characters
Spread operator	O(n)	O(n)	Converting string to array of characters