Event Loop and Concurrency

Run the following script and look at the order of its output:

console.log('Start');

setTimeout(() => {
    console.log('setTimeout');
}, 0);

Promise.resolve().then(() => {
    console.log('Promise');
});

process.nextTick(() => {
    console.log('nextTick');
});

console.log('End');

Start
End
nextTick
Promise
setTimeout

The timer asked for a delay of 0 milliseconds and was scheduled first, yet it ran last. The callback given to process.nextTick was scheduled after the promise, yet it ran before it. Both results follow from how Node