asynchronous - Async function without await in JavaScript

Question

I have two functions, a and b, that are asynchronous, the former without await and the latter with await. They both log something to the console and return undefined. After calling either of the function, I log another message and look if the message is written before or after executing the body of the function.

function someMath() {
  for (let i = 0; i < 9000000; i++) { Math.sqrt(i**5) }
}

function timeout(n) {
   return new Promise(cb => setTimeout(cb, n))
}

// ------------------------------------------------- a (no await)
async function a() {
  someMath()
  console.log('in a (no await)')
}

// ---------------------------------------------------- b (await)
async function b() {
  await timeout(100)
  console.log('in b (await)')
}

clear.onclick = console.clear

aButton.onclick = function() {
  console.log('clicked on a button')
  a()
  console.log('after a (no await) call')
}

bButton.onclick = function() {
  console.log('clicked on b button')
  b()
  console.log('after b (await) call')
}

<button id="aButton">test without await (a)</button>
<button id="bButton">test with await (b)</button>
<button id="clear">clear console</button>

Answer 1

Mozilla documentation:

An async function can contain an await expression, that pauses the execution of the async function and waits for the passed Promise's resolution, and then resumes the async function's execution and returns the resolved value.

As you assumed, if no await is present, the execution is not paused and your code will then be executed in a non-blocking manner.