How to Get the Substring Before a Character in JavaScript

Published May 7, 2020  ∙  Updated May 2, 2022

Recently, I had to manipulate a string to obtain information that followed a certain structure.

The example below is similar to what I had to do.

I wanted to get name, which was followed by a colon :.

let str = "name: description";

There were a few ways I could’ve gone about this.

Using split()

str = str.split(":")[0];

In str.split(":"), the parameter acts as a delimiter in the string, and each element is returned inside an array.

For the string above, the result is:

["name", " description"]

This is why I am accessing the zeroth element.

Using substring() and indexOf()

str = str.substring(0, str.indexOf(":"));

str.indexOf(":") returns 4, so we are obtaining the string from index 0 (inclusive) to 4 (exclusive).

Using regex

str = /(.+):/.exec(str)[0];

(.+) matches any number of word characters.

: matches, well, a colon.