Error handling in Fetch vs Axios
Derek Oware
Posted on October 12, 2020
There's so much difference between Fetch and Axios but my focus is on error handling because it caught my attention in my previous project.
Error handling is an essential part of every application we build thus needs to be done correctly.
From the fetch documentation on the difference between Fetch and JQuery, it shows how fetch handles errors differently but I don't think everyone knows about that because tutorials don't talk about that.
The issue
I think there's a good reason to why Fetch handles request failures the way it does but most devs including me usually forget to handle the result.
From the docs :
"The Promise returned from fetch()
won’t reject on HTTP error status even if the response is an HTTP 404 or 500. Instead, it will resolve normally (with ok
status set to false
), and it will only reject on network failure or if anything prevented the request from completing."
But this may be a problem is some case because in forms for instance, when the wrong data is sent to the server, we expect the attempt to fail. We may have a validation function and inside that function, if there's a success response we'd redirect the user or store the data.
The solution
In Axios, if there's request failure, it throws an error and you can easily handle the error with a try-catch
block and get the error data from error.response.data
.
In Fetch, if we have;
const res = await fetch(api);
const data = await res.json();
then, we can handle the result with;
if (!res.ok) {
error = data;
return null;
}
return data; // Do something with data if successful
Conclusion
You can check an example code on my gist or on codepen illustrating the error handling in both Fetch and Axios
Cover Photo by Markus Spiske on Unsplash
Posted on October 12, 2020
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