Octal escape sequences should be a lexical/syntactic error in strict mode and ES5

[JsonFreeman]

The following code should be disallowed in strict mode and ES5:

"\5";
"\05";
"\55";
"\055";

This is disallowed by Annex B.1.2 of the EcmaScript 5 spec.

[alexgorbatchev]

This has become an a problem since 1.8 release. I had ANSI escape codes in my TypeScript files, which were compiled to JS just fine, but 1.8 started adding use strict and all of a sudden node started freaking out.

I think a compiler error is due here if use strict is inserted.

[xogeny]

I don't quite understand the status of this issue? It is still present in 2.1.4. Is the TypeScript leaving this for the community to fix? (if so, fine...I just want to know).

I've run into this a number of times when using @basart's typestyle package to import raw css via template strings. It is very unintuitive that template strings allow embedded octal literals (since the contents of the template string are NOT TypeScript or Javascript). Nevertheless, that is the standard behavior. As such, the TypeScript compiler shouldn't be outputting invalid template strings (i.e., in my opinion the TypeScript compiler should consider an invalidate template string as an error and not emit it). It is particularly nasty when you run this gets passed through both tsc and webpack only to throw an error in the browser. At that point, it is so far downstream it is often difficult for people to trace things back to the original issue.

[sandersn]

Yes, that is what the 'Accepting PRs' label means.