\u{61} is a valid variable name in JS but not in TS

[Jack-Works]

TypeScript Version: 2.6.1

Code

var \u{61} = 1

Expected behavior:
Transpile it into var \u{61} = 1

(In Firefox)

Actual behaviour:

[sanex3339]

It's a valid variable name for es6

[mhegazy]

Duplicate of #5291

[typescript-bot]

Automatically closing this issue for housekeeping purposes. The issue labels indicate that it is unactionable at the moment or has already been addressed.