Promises to async/await

promise-function.js

// Function with a promise

const doAsyncStuff = () => {
	return new Promise((resolve, reject) => {
		if (stuff) {
			resolve('cool');
		}
		reject('bad');
	});
};

// Promise function resolution, old style

main() {
	doAsyncStuff().then(res => {
		// res === 'cool'
	}).catch(err => {
		// err === 'bad'
	});
}


// Promise function resolution, async/await style

async main() {
	try {
		const isCool = await asyncStuff();
		// isCool === 'cool'
	} catch (err) {
		// err === 'bad'
	}
}

promise-inline.js

// Inline promise resolution, old style

main() {
	new Promise((resolve, reject) => {
		if (stuff) {
			resolve('cool');
		}
		reject('bad');
	}).then(res => {
		// res === 'cool'
	}).catch(err => {
		// err === 'bad'
	});
}


// Inline promise resolution, async/await style

async main() {
	const asyncStuff = () => new Promise((resolve, reject) => {
		if (stuff) {
			resolve('cool');
		}
		reject('bad');
	});

	try {
		const isCool = await asyncStuff();
		// isCool === 'cool'
	} catch (err) {
		// err === 'bad'
	}
}