Async/await inside of Promise then [duplicate]

Question

I have a 400 returning a body with errors I need to get at. However, since fetch doesn't actually fail that status code, I handle it in the then and return a rejected Promise. But, because then generally returns a Promise, I can't issue a reject without awaiting the response from json().

dispatch({ type: 'LOGIN', payload: fetch(`${host}/api/signin/`, { method: 'POST', body: data }).then(async res => { if (res.status >= 400) { return Promise.reject(await res.json()); } return await res.json(); }) });

Is there a better way to handle this? It's technically working, but I feel like I'm probably handling it wrong by making then synchronous.

The normal process is to use two .then's, but i see no real problem with combining them using async/await. — user400654
– user400654, Commented Sep 26, 2019 at 21:36
I've created a function in my library that wraps fetch with an async function of my own and I await fetch itself within that function to avoid then completely. — Lonnie Best
– Lonnie Best, Commented Sep 26, 2019 at 21:39
I would recommend to avoid mixing await with .then(…) syntax, and to avoid return await. Also consider using response.ok instead of that .status check. — Bergi
– Bergi, Commented Sep 26, 2019 at 21:45

alex067 · Accepted Answer · 2019-09-26 21:35:23Z

-1

I feel like I am missing something here, but couldn't you just console log the rejection?

somepromise.then( res => { ... }, err => { console.log(err)} )

edited Sep 26, 2019 at 21:35

answered Sep 26, 2019 at 21:28

alex067

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3 Comments

Abishek Aditya Over a year ago

aren't you missing a , before err

TheMaster Over a year ago

fetch won't reject on 400

alex067 Over a year ago

Thanks @AbishekAditya

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