6 async syntax variations in Javascript.

nicatspark — Wed, 25 Nov 2020 10:04:14 +0000

Using async/await is prefered over the .then syntax since it makes asynchronous code look synchronous and thereby easier to read. And code is all about beeing readable, right? However it's not always super clear where to put that async command.

Async arrow functions look like this:

const foo = async () => {
  // do something
}

Async arrow functions look like this for a single argument passed to it:

const foo = async evt => {
  // do something with evt
}

Async arrow functions look like this for multiple arguments passed to it:

const foo = async (evt, callback) => {
  // do something with evt
  // return response with callback
}

The anonymous form works as well:

const foo = async function() {
  // do something
}

An async function declaration looks like this:

async function foo() {
  // do something
}

Using async function in a callback:

const foo = event.onCall(async () => {
  // do something
})

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6 async syntax variations in Javascript.