Positive lookbehind assertion not supported in JS?

JavaScript
1

I have been stuck trying to figure out regular expressions in solving a problem. I finally figured out that a positive lookbehind should work (could see in an online regex tester that it works for php) but not JS , soooo frustrating!

Is there a workaround , or do I try a different solution?

This is what I had btw for “title case a sentence”:

let regEx = /(?<= )[a-z]/g;

There’s a space to the right of the = btw , but it doesn’t render correctly here.
so it should highlight the first letter of each word. But not in js, it seems , even though MDN has a tutuorial all about assertions in JS with this assertion.

Thanks for the rant.

2

Okay is there a link to the challenge you got stuck onto?
Also if you want to know the other way it is possible but, it’s much more advanced. and i would’t recomend to use it. FCC is set to help beginners there is logic behind the reasoning and this lesson which you might not have yet comprhended yet.

3

Chrome as support for Lookbehind and it seems like the challenge isn’t throwing an error when using it (not sure if it will work as I didn’t test it).

It would help if you showed how you are planning to use the regex exactly. Did you try and log out using it with a match?

let regEx = /(?<= )[a-z]/g;

"I'm a little tea pot".match(regEx)
// ["a", "l", "t", "p"]

"sHoRt AnD sToUt".match(regEx)
// ["s"]

"HERE IS MY HANDLE HERE IS MY SPOUT".match(regEx)
// null

You don’t need to use Lookbehind (or a regex for that matter).

This is the challenge BTW.

4

Thanks for the replies, I don’t understand how all the tutorials explain lookbehinds for JS, yet there doesn’t seem to be support for it , JS doesn’t support it .
So I’ll have to figure out another solution. I tried in Chrome it didn’t work, but thanks for the replies :slight_smile: