Word boundaries in Atlas Search regex operator

I use the regex operator in my MongoDB Atlas search because the data is indexed using a keyword analyzer, meaning that the whole string of a field is indexed as one single “word”.

Because of this, exact word matches don’t work like they would with the default analyzer. If the title of a document is JavaScript beginner tutorial then a search for JavaScript will not match. Instead, I use regex wildcards to find single words within this larger string. Which looks like this:

'(.*)' + 'JavaScript' + '(.*)'

This works. However, I want to give exact word matches an extra boost in the search score. Hence I want to run an additional regex query that looks for either only whitespace before or after the word, or the word being at the beginning and/or end of the string.

For example, when I search for Java, I want Java beginner tutorial to rank higher than JavaScript beginner tutorial. Currently, this is not the case, because the wildcards look for any characters.

The normal Regex operators don’t seem to work with the Atlas regex search. I tried things like word boundaries \bJava\b or others, but none of them had an effect.