Event Loop & Microtasks

What is the complete output sequence?

console.log('Start');

setTimeout(() => console.log('Timeout 1'), 0);
setTimeout(() => console.log('Timeout 2'), 0);

Promise.resolve()
  .then(() => console.log('Promise 1'))
  .then(() => console.log('Promise 2'));

console.log('End');

Start, End, Timeout 1, Timeout 2, Promise 1, Promise 2
Start, End, Promise 1, Promise 2, Timeout 1, Timeout 2
The sequence demonstrates the complete event loop priority: 1) Synchronous code executes first (Start, End), 2) All microtasks (Promise callbacks) execute before any macrotasks, 3) Promise chain creates sequential microtasks, 4) setTimeout callbacks are macrotasks and execute last, 5) Multiple macrotasks execute in scheduling order, 6) This pattern is crucial for understanding complex async workflows.
Start, Promise 1, Promise 2, End, Timeout 1, Timeout 2
Start, End, Promise 1, Timeout 1, Promise 2, Timeout 2

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