Support jest-function for Typescript-mode

[davazp]

The jest-function uses js2, so it does not work on other modes like typescript-mode.

A few ideas:

• one option could be to just add code to get the same information from other modes.
• another one could be to have some basic heuristics and not rely on js2-mode at all. So using some basic regular expressions to extract the path of describe/it strings.
• Maybe another libraries like like lsp, imenu, could be used?

[lazyskulptor]

I made a function extracting test name from buffer. Please check and give some advices to improve.

#25

[PierreRambaud]

is it possible to go further with this PR, it's really interesting?
If the maintainer is not able to test and do something, maybe some people are interesting to help :)

[edmundmiller]

is it possible to go further with this PR, it's really interesting? If the maintainer is not able to test and do something, maybe some people are interesting to help :)

Thanks for reviewing that! I haven't been writing much JS myself recently, so I haven't been using it.

I used this repo to test however in case that's of use in the future, so we can reproduce results https://github.com/Lemoncode/jest-testing-by-sample/tree/master/frontend/02%20Plain%20Vanilla

[lazyskulptor]

is it possible to go further with this PR, it's really interesting?
If the maintainer is not able to test and do something, maybe some people are interesting to help :)

Thanks for review. I found some bugs on my code.
When there are special symbols in test name, It doesn't work.
ASAP I will try to fix it.