Catching errors using links

[apollographql]

Catching errors using links

@valerybugakov take a look at apollo-error-link

Compose this with your httpLink like this:

import { ApolloClient } from 'apollo-client';
import { ApolloLink } from 'apollo-link';
import { createHttpLink } from 'apollo-link-http';
import { onError } from 'apollo-link-error';
import { InMemoryCache } from 'apollo-cache-inmemory';

const errorLink = onError(({ networkError, graphQLErrors }) => {
  if (graphQLErrors) {
    graphQLErrors.map(({ message, locations, path }) =>
      console.log(
        `[GraphQL error]: Message: ${message}, Location: ${locations}, Path: ${path}`,
      ),
    );
  }
  if (networkError) console.log(`[Network error]: ${networkError}`);
});

const httpLink = createHttpLink({ ... });

const link = ApolloLink.from([
  ...otherLinksIfNeeded,
  errorLink,
  httpLink,
]);

const client = new ApolloClient({
  link,
  cache: new InMemoryCache(),
  queryDeduplication: true,
});

[coyolero]

@jbaxleyiii
What about if I want to catch a network Error?
Lets say a 400, bad request.

[valerybugakov]

@somehandle yep, it's an option. What if I want to handle errors in my custom link? I found the only way to do it is to wrap Observable returned by next(operation) into another Observable.

[jbaxleyiii]

@valerybugakov what kind of errors do you want to handle? If they are Graphql Errors, you can use .map on the result of forward(operation) since they are returned as a result, if not, you need to subscribe around the other observer. Take a look at the code behind apollo-link-error for some examples!

[vjpr]

@coyolero Related #570