Syntax for an async arrow function

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?

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
}

This the simplest way to assign an async arrow function expression to a named variable:

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

_{(Note that this is not strictly equivalent to async function foo() { }. Besides the differences between the function keyword and an arrow expression, the function in this answer is not "hoisted to the top".)}

Immediately Invoked Async Arrow Function:

(async () => {
    console.log(await asyncFunction());
})();

Immediately Invoked Async Function Expression:

(async function () {
    console.log(await asyncFunction());
})();

Async Arrow function syntax with parameters

const myFunction = async (a, b, c) => {
   // Code here
}

Basic Example

folder = async () => {
    let fold = await getFold();
    //await localStorage.save('folder');
    return fold;
  };

async function foo() {
  // do something
}

Is equivalent to:

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

Calling foo with one argument like in the following example:

async function foo(arg1) {
  // do something
}

Is equivalent to calling foo like this (both ways are acceptable since parentheses are optional but not required when just one argument is provided)

const foo = async arg1 => {
  // do something
}

const foo = async (arg1) => {
  // do something
}

if you call foo with two or more arguments

async function foo(arg1, arg2) {
  // do something
}

Is equivalent to: (parentheses are now required)

 const foo = async (arg1, arg2) => {
    // do something
 }

And for a practical example with an await use inside:

const foo = async () => await Promise.resolve('done');

You may also do:

 YourAsyncFunctionName = async (value) => {
 
    /* Code goes here */

}

My async function

const getAllRedis = async (key) => {
  let obj = [];

  await client.hgetall(key, (err, object) => {
    console.log(object);
    _.map(object, (ob)=>{
      obj.push(JSON.parse(ob));
    })
    return obj;
    // res.send(obj);
});
}