Error handling with fakeBaseQuery (RTK Query streaming updates)

[morzel85]

What is the recommended way of handling errors while using streaming updates?
Is there a way to setup RTKQ createApi in such a way that errors thrown from onCacheEntryAdded or updateCachedData affect the isError property returned by API hook?

[seandinwiddie]

When using RTK Query with streaming updates, error handling can be a bit more complex. Here are some recommendations on how to handle errors:

1. Use onError callback in fetchBaseQuery

You can pass an onError callback to fetchBaseQuery to catch errors that occur during the fetch process. This callback will be called with the error as an argument.

import { fetchBaseQuery } from '@reduxjs/toolkit/query/react';

const baseQuery = fetchBaseQuery({
  baseUrl: 'https://my-api.com',
  onError: (error) => {
    console.error('Error occurred:', error);
    // You can also dispatch an error action or update the state here
  },
});

2. Use retry option in fetchBaseQuery

You can also use the retry option to specify a retry policy for failed requests. This can help handle temporary errors or network issues.

const baseQuery = fetchBaseQuery({
  baseUrl: 'https://my-api.com',
  retry: (failureCount, error) => {
    if (failureCount < 3) {
      return true; // retry up to 3 times
    } else {
      return false; // give up after 3 retries
    }
  },
});

3. Catch errors in onCacheEntryAdded and updateCachedData

To catch errors thrown from onCacheEntryAdded or updateCachedData, you can wrap these functions in a try-catch block.

import { createApi } from '@reduxjs/toolkit/query/react';

const api = createApi({
  reducerPath:'myApi',
  baseQuery: baseQuery,
  endpoints: (builder) => ({
    getItems: builder.query({
      query: () => 'items',
      onCacheEntryAdded: (cacheEntry, { updateCachedData }) => {
        try {
          // code that might throw an error
        } catch (error) {
          console.error('Error in onCacheEntryAdded:', error);
          // You can also dispatch an error action or update the state here
        }
      },
      updateCachedData: (cacheEntry, { updateResult }) => {
        try {
          // code that might throw an error
        } catch (error) {
          console.error('Error in updateCachedData:', error);
          // You can also dispatch an error action or update the state here
        }
      },
    }),
  }),
});

4. Use isError property in API hook

To affect the isError property returned by the API hook, you can throw an error from the onError callback or from within the onCacheEntryAdded or updateCachedData functions. This will set the isError property to true and provide the error message as the error property.

import { useGetItemsQuery } from './api';

const { data, error, isError } = useGetItemsQuery();

if (isError) {
  console.error('Error:', error);
  // Handle error here
}

By following these recommendations, you should be able to handle errors effectively when using RTK Query with streaming updates.

[EskiMojo14]

chatGPT-tastic

fetchBaseQuery doesn't have onError or retry options, and updateCacheData isn't a valid endpoint key