async/await IIFE

Question

Would anyone be so kind to assist me if I’m ‘cooking’ async/await a right way?

I attend to return an express response once promise to DB resolves.

router.get('/', (req, res, next) => {
 (async function() {
 try {
 const cases = await db.collections.cases.stats();
 return res.render('index', {
 title: 'Welcome',
 totalDBRecords: cases.count,
 });
 }
 catch (e) {
 console.error(e);
 next(e);
 }
 })();
});

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Answer 1

I don't think you need to wrap this in an IFFE. You can simply write the async function as follows:

router.get('/', async (res, req, next) => {
 try {
 const cases = await db.collections.cases.stats();
 res.render('index', {
 title: 'Welcome',
 totalDBRecords: cases.count,
 });
 } catch(err) {
 console.log(err);
 next(err);
 }
});

That should work. I also like the way Wes Bos wraps his functions in an error handler, like so (eliminates having to use try/catch).

const catchErr = (fn) => {
 return function(res, req, next) {
 fn(req, res, next).catch(next);
 }
}; 
const home = async (res, req, next) => {
 const cases = await db.collections.cases.stats();
 res.render('index', {
 title: 'Welcome',
 totalDBRecords: cases.count,
 });
};
router.get('/', catchErr(home));

• Coderbit: Thanks for your input. I really like the 'Wes Bos' version, especially its readability.
• Calvin Koepke: He has a great course on learning Node, if you're interested: learnnode.com