javascript replace all with case insensitive and keeping correct case in original string

Question

My problem is i want to do something like this:

Javascript vaja => <b>Ja</b>vascript va<b>ja</b> ie i have a query string(ja) and i want to replace all the occurances(case insensitive) of that query string in a bigger string (Javascript vaja).

The closest solution i have right now is:

"Javascript vaja".replace(/ja/gi, '<b>ja</b>');

which gives me:

"<b>ja</b>vascript va<b>ja</b>"

but what i need is:

Javascript vaja => <b>Ja</b>vascript va<b>ja</b>

one solution that i have in mind is to keep the indexes of upcase letters before replacement and then re replace them. But that is way too hacky. I am pretty sure i am not the first one trying this and pretty sure there is some elegant and simpler solution hidden somewhere.

Answer 1

Simply use a capturing group:

"Javascript vaja".replace(/(ja)/gi, '<b>$1</b>');

See this working demo.

Edit: Read more about capturing groups here.