How to split a string based of capital letters?

Question

I have a string I need to split based on capital letters,my code below

let s = 'OzievRQ7O37SB5qG3eLB';
var res = s.split(/(?=[A-Z])/)
console.log(res);

But there is a twist,if the capital letters are contiguous I need the regex to "eat" until this sequence ends.In the example above it returns

..R,Q7,O37,S,B5q,G3e,L,B

And the result should be

RQ7,O37,SB5q,G3e,LB

Thoughts?Thanks.

Answer 1

You need to match these chunks with /[A-Z]+[^A-Z]*|[^A-Z]+/g instead of splitting with a zero-width assertion pattern, because the latter (in your case, it is a positive lookahead only regex) will have to check each position inside the string and it is impossible to tell the regex to skip a position once the lookaround pattern is found.

s = 'and some text hereOzievRQ7O37SB5qG3eLB';
console.log(s.match(/[A-Z]+[^A-Z]*|[^A-Z]+/g));

See the online regex demo at regex101.com.

Details:

• [A-Z]+ - one or more uppercase ASCII letters
• [^A-Z]* - zero or more (to allow matching uppercase only chunks) chars other than uppercase ASCII letters
• | - or
• [^A-Z]+ - one or more chars other than uppercase ASCII letters (to allow matching non-uppercase ASCII letters at the start of the string.

The g global modifier will let String#match() return all found non-overlapping matches.