How to split a string by uppercase and lowercase in JavaScript?

Question

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);

Seems to be a duplicate of http://stackoverflow.com/a/7599674/586030 — Aaron Cicali, May 10 '16 at 00:31
Give this a try: `/(?:[A-Z]+|[^A-Z]+)/g` https://regex101.com/r/hR3kE3/1 — , May 10 '16 at 00:36
that worked perfectly, squint - however, I can't set Q as answered as you posted a comment — Haloor, May 10 '16 at 00:43
Glad it helped. You've got other answers below you can mark. — , May 10 '16 at 00:44
duplicate [Javascript Split string on UpperCase Characters](http://stackoverflow.com/questions/7888238/javascript-split-string-on-uppercase-characters) — Baby, May 11 '16 at 00:44

score 10 · Accepted Answer · answered May 10 '16 at 00:39

10

([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

answered May 10 '16 at 00:39

yelsayed

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score 4 · Answer 2 · answered May 10 '16 at 00:43

4

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('!!');

answered May 10 '16 at 00:43

omarjmh

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score 0 · Answer 3 · answered Jul 28 '20 at 04:39

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('!');
};

How to split a string by uppercase and lowercase in JavaScript?

3 Answers3

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