updates to EscapedChars.md

[bergus]

as suggested in #31

[bergus]

Uh, wait, is the following behaviour (tested in my browser console) actually buggy?

>>> new RegExp("\\u41" + "B").test("u41B")
false
>>> new RegExp("\\u41" + "B").test("\u041B")
true

If I append a non-hexadecimal character, it matches the literal letters (and treats \u as an IdentityEscape):

>>> new RegExp("\\u41" + "B%").test("u41B%")
true
>>> new RegExp("\\u41" + "B%").test("\u041B%")
false

[domenic]

Chrome has some bugs in this area, so definitely test a few browsers.

[bergus]

The test above was in (old) Opera. But before testing browsers, I wanted to get a confirmation that I've correctly understood the spec and the first snippet demonstrates a bug?

[anba]

But before testing browsers, I wanted to get a confirmation that I've correctly understood the spec and the first snippet demonstrates a bug?

The first snippet should give the following output (*):

js> new RegExp("\\u41" + "B").test("u41B")
true
js> new RegExp("\\u41" + "B").test("\u041B")
false

For Unicode enabled RegExps (or implementations without support for extension "B.1.4 Regular Expressions Patterns"), new RegExp("\\u41" + "B") throws a SyntaxError.

(*): Also tested in Edge, V8, JavaScriptCore, Nashorn and SpiderMonkey

[benjamingr]

Thanks @bergus !