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We already have the logic to "unraw" template literals in our parser, I wonder if we could extract it from there to have a single implementation.

@nicolo-ribaudo
The logic in parser is quite coupled, and keeping a single implementation seems difficult to do.
Actually I also tried to extract the code from parser at first, but didn't find it. 😓
I tried again just now and found it, but it looks like it's hard to even copy a copy of the code and modify it.

@nicolo-ribaudo
I'm trying helper-string-parser and I'm having a little problem.
This way unterminatedCalled is true when raw is any value.

readStringContents("template", raw, 0, 0, 0, {
              unterminated() {
                unterminatedCalled = true;
              },
              strictNumericEscape: error,
              invalidEscapeSequence: error,
              numericSeparatorInEscapeSequence: error,
              unexpectedNumericSeparator: error,
              invalidDigit: error,
              invalidCodePoint: error,
            })

I think it's not true when raw is

abc`def

(which is actually an invalid raw, so we can throw if unterminatedCalled remains false)

I'm not quite sure how I should use it.😕

Try this:

let unterminatedCalled = false;
let str, containsInvalid;
try {
  const error = () => {
    throw new Error();
  };
  ({ str, containsInvalid } = readStringContents(
    "template",
    "abc\\u{1000_0000}",
    0,
    0,
    0,
    {
      unterminated() {
        unterminatedCalled = true;
      },
      strictNumericEscape: error,
      invalidEscapeSequence: error,
      numericSeparatorInEscapeSequence: error,
      unexpectedNumericSeparator: error,
      invalidDigit: error,
      invalidCodePoint: error,
    }
  ));
} catch {
  // TODO: When https://github.com/babel/babel/issues/14775 is fixed
  // we can remove the try/catch block.
  unterminatedCalled = true;
  containsInvalid = true;
}

if (!unterminatedCalled) throw new Error("Invalid raw");

cooked = containsInvalid ? null : str;

some tests:

"abcdef"; // ok
"abc\u{123}def"; // ok
"abc\u{}def"; // null cooked
"abc\u{10000_0000}def"; // null cooked
"abc`def"; // Invalid raw, error
"abc`"; // Invalid raw, error
"`abc"; // Invalid raw, error
"abc${"; // Invalid raw, error
"${abc"; // Invalid raw, error
"abc\\`"; // ok

It's weird.
Is str being '' expected?

Whops sorry, it's a bug in helper-string-parser (that does not affect @babel/parser): can you add out += input.slice(chunkStart, pos); after the first error.unterminated?

Now it works fine!

@liuxingbaoyu do you know when this is going to be released?

I'm not sure, generally released by @nicolo-ribaudo and @JLHwung .

I can release later today!