console.log('A');
setTimeout(() => console.log('B'), 0);
Promise.resolve().then(() => console.log('C'));
console.log('D');I said A D B C, answer is A D C B. why does the promise go before a 0ms timeout
Promise callbacks go to the microtask queue, setTimeout goes to the task (macrotask) queue. After the current script finishes, the event loop runs all microtasks first, then one task.
So A, D (sync), C (microtask), B (task). 0ms just means "not before 0ms", not "right now".
harder version: setTimeout inside a then and a then inside a setTimeout. same rule, just go step by step
this exact question came in my Juspay interview 🥲
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