/** * What will be printed to the console and why */ const a = () => console.log('a'); const b = () => setTimeout(() => console.log('b'), 0); const c = () => Promise.resolve().then(() => console.log('c')); a(); b(); c();

The console will output in the following order:

a
c
b

Explanation:

• a() — a synchronous function that immediately outputs 'a'.
• b() — calls setTimeout with a delay of 0, which places the callback in the macro task queue; it will execute after all microtasks and the current call stack.
• c() — creates a promise that resolves immediately, and its .then places the callback in the microtask queue.

The JavaScript event loop first executes all synchronous operations, then microtasks (promises), and only then macro tasks (setTimeout). Therefore, the output order is 'a', then 'c', then 'b'.