What are process.nextTick() and setImmediate()? How do they differ?

• process.nextTick() queues a callback to be invoked immediately after the

current operation completes, before the event loop continues.

• setImmediate() queues a callback to run on the next iteration of the event loop.

Example:

process.nextTick(() => console.log('nextTick'));
setImmediate(() => console.log('setImmediate'));

console.log('sync');

Output:

sync

nextTick

setImmediate

nextTick runs before any I/O or timers; setImmediate runs after I/O callbacks.