How to handle HTTP code 4xx responses in fetch api

by

I’d suggest a wrapper that checks response.ok which will be true if the response code is 2xx.

Note this statement from the MDN page on fetch():

An accurate check for a successful fetch() would include checking that
the promise resolved, then checking that the Response.ok property has
a value of true. An HTTP status of 404 does not constitute a network
error.

Here is a wrapper like this:

function fetchData() {
    return fetch.apply(null, arguments).then(response => {
         if (!response.ok) {
             // create error object and reject if not a 2xx response code
             let err = new Error("HTTP status code: " + response.status)
             err.response = response
             err.status = response.status
             throw err
         }
         return response
    })
}

More Related Contents:

  1. Why does .json() return a promise?
  2. How can I fetch an array of URLs with Promise.all?
  3. fetch: Reject promise with JSON error object
  4. fetch resolves even if 404?
  5. using a fetch inside another fetch in javascript
  6. What’s wrong with awaiting a promise chain?
  7. Issue in returning data retrieved from DB queries called in the loop
  8. JavaScript Promises – reject vs. throw
  9. How to include multiple js files using jQuery $.getScript() method
  10. Node JS Promise.all and forEach
  11. Getting “TypeError: Failed to fetch” when the request hasn’t actually failed
  12. How to check if an object is a Promise?
  13. JavaScript array .reduce with async/await
  14. Nodejs express and promises not doing what I expect
  15. How do I use Bluebird with Angular?
  16. Fetch API vs XMLHttpRequest
  17. Using JavaScript Axios/Fetch. Can you disable browser cache?
  18. How to do promise.all for array of array of promises?
  19. How to structure nested Promises
  20. How can I access the value of a promise?
  21. What are asynchronous functions in JavaScript? What is “async” and “await” in JavaScript?
  22. What is the intention behind clause 2.2.4 of Promise/A+ spec?
  23. Limit concurrency of pending promises
  24. typescript: error TS2693: ‘Promise’ only refers to a type, but is being used as a value here
  25. How to fetch XML with fetch api
  26. How to make javascript fetch synchronous?
  27. set withCredentials to the new ES6 built-in HTTP request API : Fetch
  28. When or who does pass resolve and reject functions to JS promises?
  29. What happens when promise is yielded in javascript?
  30. When is the body of a Promise constructor callback executed?

Leave a Comment