benhowdle89 benhowdle89 - 1 month ago 13
Javascript Question

ES6: Bad character escape sequence creating ASCII string

Here's my code:

let padded = "03";
ascii = `\u00${padded}`;


However, I receive
Bad character escape sequence
from Babel. I'm trying to end up with:

\u0003


in the
ascii
variable. What am I doing wrong?

EDIT:

Ended up with
ascii = (eval('"\\u00' + padded + '"'));

Answer

What am I doing wrong?

A unicode escape sequence is basically atomic. You cannot really build one dynamically. Template literals basically perform string concatenation, so your code is equivalent to

'\00' + padded

It should be obvious now why you get that error. If you want to get the corresponding unicode character you can instead use String.fromCodePoint or String.fromCharCode:

String.fromCodePoint(3)

If you want a string that literally contains the character sequence \u0003, then you just need to escape the escape character to produce a literal backslash:

`\\u00${padded}`