index.js

code.js

if ('a'.replace(/\//g, '')) {
  // something
}

index.js

const fs = require('fs');

const re1 = /((?:(?:^\h*)?(?:\/\*[^*]*\*+(?:[^\/*][^*]*\*+)*\/(?:\h*\n(?=\h*(?:\n|\/\*|\/\/)))?|\/\/(?:[^\\]|\\\n?)*?(?:\n(?=\h*(?:\n|\/\*|\/\/))|(?=\n))))+)|("(?:\\[\S\s]|[^"\\])*"|'(?:\\[\S\s]|[^'\\])*'|[\S\s][^\/"'\\\s]*)/gm;
const re2 = /((?:(?:^[ \t]*)?(?:\/\*[^*]*\*+(?:[^\/*][^*]*\*+)*\/(?:[ \t]*\r?\n(?=[ \t]*(?:\r?\n|\/\*|\/\/)))?|\/\/(?:[^\\]|\\(?:\r?\n)?)*?(?:\r?\n(?=[ \t]*(?:\r?\n|\/\*|\/\/))|(?=\r?\n))))+)|("(?:\\[\S\s]|[^"\\])*"|'(?:\\[\S\s]|[^'\\])*'|(?:\r?\n|[\S\s])[^\/"'\\\s]*)/gm;

const code = fs.readFileSync('./code.js').toString();

console.log(code.replace(re1, '$2'));
console.log(code.replace(re2, '$2'));

$ node index.js

if ('a'.replace(/\

}

if ('a'.replace(/\
}

This is wrong. Re/ https://stackoverflow.com/a/59147511/458177