SWC minifier un-escapes unicode characters

[slorber]

Describe the bug

For some code inputs containing escaped unicode emojis, SWC minifier will output unescaped unicode emojis.

Example input:

console.log("\\"\\\\uD83D\\\\uDE42\\"");

Input code

import swc from '@swc/core';

const input = `
console.log("\\"\\\\uD83D\\\\uDE42\\"");
`;

console.log('input');
console.log(input);
eval(input);

console.log('\n');
const output = await swc.minify(input);

console.log('output');
console.log(output.code);
eval(output.code);



Runnable playground: https://stackblitz.com/edit/stackblitz-starters-gpln2upu

Output:


❯ node index.js

input
console.log("\"\\uD83D\\uDE42\"");
"\uD83D\uDE42"


output
console.log('"\uD83D\uDE42"');
"🙂"

Config

Link to the code that reproduces this issue

https://play.swc.rs/?version=1.11.18&code=H4sIAAAAAAAAA1OKiSl1sTB2UQIAWPmpCAkAAAA%3D&config=H4sIAAAAAAAAA1VQuW7DMAzd8xWC0KkorCBjpgxdM3YqMrAyfcGSDJJGawT590qOY8uT%2Fch3ifeDUsYo%2Fca2QQf6rHQjMvDZmI6DL55jlkBYBKoN%2F1qy%2BiOqNIeRLF5h4KgSGnGedmwjvMffCAYgRlpxEk1e4C%2FFyDQgW2oHme3mbYk2EMSw3FKpx%2FOjhcBzFcjljj3WYKfPl3InzC2vKFCCwIswr%2Ff2QDVK6oZ8Op6OS6%2F4Cmk4j7y4UI49snmP02%2B9odsae7HBV229MFaQEbgBwnIhrOC2a%2FQDjF%2FUp0qF4eXw83IJ3U6dzpl4NjgXfMd6Y7a%2Brab1Lo%2FDP5Tvfnb0AQAA

SWC Info output

After being minified, if the unicode chars are escaped, they should also be escaped in the output

\\uD83D is not equivalent to \uD83D

Expected behavior

\\uD83D should remain \\uD83D

Actual behavior

\\uD83D is unescaped to \uD83D

Version

1.11.18

Additional context

Prettier website bug: prettier/prettier#17308

Docusaurus bug report: facebook/docusaurus#11047