Page 130 - JavaScript

return await response.json();
}
catch (err) {
// Rejections in the promise will get thrown here
console.error(err.message);
}
}

An async function always returns a Promise itself, so you can use it in other asynchronous
functions.

Arrow function style

const getJSON = async url => {
const response = await fetch(url);
return await response.json();
}

Less indentation

With promises:

function doTheThing() {
return doOneThing()
.then(doAnother)
.then(doSomeMore)
.catch(handleErrors)
}

With async functions:

async function doTheThing() {
try {
const one = await doOneThing();
const another = await doAnother(one);
return await doSomeMore(another);
} catch (err) {
handleErrors(err);
}
}

Note how the return is at the bottom, and not at the top, and you use the language's native error-
handling mechanics (try/catch).

Await and operator precedence

You have to keep the operator precedence in mind when using await keyword.

Imagine that we have an asynchronous function which calls another asynchronous function,
getUnicorn() which returns a Promise that resolves to an instance of class Unicorn. Now we want to

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