How to Capitalize Words in JavaScript

If you want to capitalize words in JavaScript, you can use the following function which makes use of replace, toUpperCase and some regex:

const capitalize = str => str.replace(/\b\w/g, substr => substr.toUpperCase());

// This will return: "Lorem Ipsum Dolor Sit Amet..."
capitalize('lorem ipsum dolor sit amet...');

The regex for the string replace uses an anchor and a word boundary to match the first character of every word. If you need to capitalize only the very first letter of your string, you can use the following solution:

const capitalize = str => str.charAt(0).toUpperCase() + str.slice(1).toLowerCase();

// This will return: "Lorem ipsum dolor sit amet..."
capitalize('lorem ipsum dolor sit amet...');

// This also works for wrong capitalizations:
capitalize('lOREM IPsUm dolor sit amet...');

This function will get the first character of your string (charAt(0)), turn it into uppercased, and then slice(1) returns the rest of the string, lowercased.

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Resources:

• String replace
• toUpperCase
• toLowerCase
• charAt
• Array.prototype.slice