1console.error("I'm sorry, Dave. I'm afraid I can't do that.");

1console.time();for (var i = 0; i < 100000; i++) {  let square = i ** 2;}console.timeEnd();

1const first = () => { second(); };const second = () => { third(); };const third = () => { fourth(); };const fourth = () => { console.trace(); };first();

1const x = 5;const y = 3;const reason = 'x is expected to be less than y';console.assert(x < y, {x, y, reason});