Split a string in JavaScript

David Y.

The problem

How do I split a string in JavaScript?

The solution

We can use JavaScript’s String.prototype.split() method. When called on a string, this will split the string at every instance of the provided separator, discard the separator, and return an array of substrings. The following code provides an example:

const myString = "This is a sentence.";
const words = myString.split(" "); // split on single space characters

console.log(words); // will output ["This", "is", "a", "sentence."]

The separator can be a string or a regular expression, so we could also do something like this:

const myString = "This is a sentence.";
const words = myString.split(/[ t]/); // split on single space characters and lowercase t's

console.log(words); // will output ["This", "is", "a", "sen", "ence."]

If we would like to retain the separator when splitting, we can use a regular expression with a positive lookahead assertion, as below:

const myString = "This is a sentence.";
const words = myString.split(/(?= )/); // split on but retain single space characters

console.log(words); // will output ["This", " is", " a", " sentence."]

We can also truncate the final array by setting the optional limit parameter:

const myString = "This is a sentence.";
const words = myString.split(" "); // split on single space characters
words.length = 3;

console.log(words); // will output ["This", "is", "a"]