RegExp literal fixes

[shinew]

See #263.

There's a comment I made in the code about the need to prettify let a = / /; into let a = /\t\;, which have the same behavior. This makes the generated literal more clear, at the cost of 1-3 extra characters per invisible newline character when minified. I'm not convinced this beautification is necessary since it's generated code anyway.

Thoughts?

[kangax]

I think we shouldn't bother with "\t" similar to how we don't do this w. Babel literals and minified=true.

Does this work with backslash escapes?

new RegExp('https?:\\/\\/(?:[\\dA-Za-z\\-]+\\.)+[\\dA-Za-z\\-]+(?::\\d+)?\\/[^\\s]*')

[shinew]

Yeah, that case works I think.
Output string is: "var x = /https?:\\/\\/(?:[\\dA-Za-z\\-]+\\.)+[\\dA-Za-z\\-]+(?::\\d+)?\\/[^\\s]*/;", corresponding to the code:var x = /https?:\/\/(?:[\dA-Za-z\-]+\.)+[\dA-Za-z\-]+(?::\d+)?\/[^\s]*/;. Running 'https://github.com/babel/babili/pull/264'.replace(x, '') in the console returns "".

[kangax]

Strange, I'm seeing test failure on travis — https://travis-ci.org/babel/babili/jobs/175548633 — but not locally

[kangax]

Actually, no there's failures locally too. @shinew could you please take a look when you get a chance.

[shinew]

My bad -- forgot to update test after restoring the \t literal.