reducer option ignored by query and watchQuery

[daniel-nagy]

Both ApolloClient::query and ApolloClient::watchQuery list reducer as an option. The query method seems to ignore the option and watchQuery only calls the reducer if you create a subscription as well. I'm not sure if this is intended but it wasn't what I expected.

version: 0.8.3
framework: React Native

Intended outcome

If I provide reducer as an option to query or watchQuery I would expect it to be invoked every time a query returns a new result.

Actual outcome

My reducer is ignored unless I also add a subscription on the observable returned from watchQuery.

Reproduction

Create a query with ApolloClient::query and provide a reducer as an option.

client.query({
  query: ...
  reducer(result, action) {
    // never called
  }
});

[calebmer]

@daniel-nagy could you use updateQueries instead?

[helfer]

Could this be a duplicate of #1129?

[helfer]

Btw, reducer should not be an option on query, only on watchQuery. We're likely to remove this API in upcoming versions (at least temporarily) for the reasons mentioned in #1129.

[calebmer]

Closing this issue. We don’t recommend using reducer. Please use updateQueries or update instead.

[m14t]

@calebmer according to http://dev.apollodata.com/react/cache-updates.html#resultReducers

We recommend using the reducer option, except when there’s a good reason to use updateQueries instead (eg. if it would make your app much easier to understand and maintain).

To me that sounds like reducer is the preferred way? If that's not the case would it be possible to update that doc?

https://github.com/apollographql/react-docs/blame/master/source/cache-updates.md#L291

[helfer]

@m14t yeah, reducer isn't the recommended way any more. We think update is much more versatile and will be a stable API in the future. Would you mind making a PR to the docs to change that sentence? There's a "edit on GitHub" button on every page.

[m14t]

Thanks for the speedy reply @helfer. I'm actually quite new to Apollo and so re-writing that paragraph which does not currently reference update is a slightly nuanced task for my current knowledge level.

[helfer]

Haha, no worries, I hope you're liking it so far! I'll update the docs as soon as I get around to it.