Are the two js statements always returning the same result? s.replace(/\t/g, '|') vs s.split('\t').join('|')

Assuming that input_string is a plain string, and that none of the build-in methods String.prototype.replace, String.prototype.split, Array.prototype.join have been tampered with - then no, .replace followed by .join in that matter will always produce the same output.

If you allow for the possibility that the methods have been patched, then all bets are off.

String.prototype.replace = () => '';
console.log('foo'.replace(/\t/g, '|'));