Is it possible to split Strings in JavaScript by case such that the following string below (myString) would be converted into the array (myArray) below:

var myString = "HOWtoDOthis";
var myArray = ["HOW", "to", "DO", "this"];

I have tried the regex below, but it only splits for camelCase:

.match(/[A-Z]*[^A-Z]+/g);

Is it possible to split Strings in JavaScript by case such that the following string below (myString) would be converted into the array (myArray) below:

var myString = "HOWtoDOthis";
var myArray = ["HOW", "to", "DO", "this"];

I have tried the regex below, but it only splits for camelCase:

.match(/[A-Z]*[^A-Z]+/g);

• javascript
• regex

• Seems to be a duplicate of stackoverflow.com/a/7599674/586030 – Aaron Cicali Commented May 10, 2016 at 0:31
• 2 Give this a try: /(?:[A-Z]+|[^A-Z]+)/g regex101.com/r/hR3kE3/1 – user1106925 Commented May 10, 2016 at 0:36
• that worked perfectly, squint - however, I can't set Q as answered as you posted a comment – Haloor Commented May 10, 2016 at 0:43
• Glad it helped. You've got other answers below you can mark. – user1106925 Commented May 10, 2016 at 0:44
• duplicate Javascript Split string on UpperCase Characters – Baby Commented May 11, 2016 at 0:44

3 Answers 3

([A-Z]+|[a-z]+). Match all upper case, or all lower case multiple times in capturing groups. Give this a try here: https://regex101.com/r/bC8gO3/1

Another way to do this is to add in a marker and then split using that marker, in this case a double-exclamation point:

JsBin Example

var s = "HOWtoDOthis";

var t = s.replace(/((?:[A-Z]+)|([^A-Z]+))/g, '!!$&').split('!!');

If you want to split an CamelCased String following will work

/**
 * howToDoThis ===> ["", "how", "To", "Do", "This"]
 * @param word word to be split
 */
export const splitCamelCaseWords = (word: string) => {
    if (typeof word !== 'string') return [];
    return word.replace(/([A-Z]+|[A-Z]?[a-z]+)(?=[A-Z]|\b)/g, '!$&').split('!');
};