Syntax for an async arrow function

Question

I can mark a JavaScript function as "async" (i.e., returning a promise) with the async keyword. Like this:

async function foo() {   // Do something } 

What is the equivalent syntax for arrow functions?

Answer 1

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 }) 

Using async method inside of a class:

async foo() {   // do something }