Manually update the ferry data

[simplenotezy]

Let's say you have a normal query (https://ferrygraphql.com/docs/queries) but you wish to programatically update the data, depending on some other logic; how can this be done?

Or even build a request with som predefined data / set the cache with some predefined data?

The issue is that I have a query to fetch all genres, and for each genre, there's 10 movies. When you scroll further in the movie list, I need to load 10 more movies (but not 10 more genres).

One way to achieve this would be to have a query to fetch movies for a genre; and when you fetch the genres list, the cache for the queries to fetch movies is set to the data from the genres query.

[knaeckeKami]

Yes, there are multiple points where you could hook in.
I'm not sure what your schema and queries look like, so it's difficult to give concrete advice.

But general pointers are:
The .request() method returns a stream, and the stream keeps listening to cache updates.

So you can

• manually update cache data using cache.writeQuery(), cache.writeFragment()
• update the cache in response to other queries using cache handlers https://ferrygraphql.com/docs/mutations#updating-the-cache
• using typehelpers to structure your cache to merge queries that use paging, see https://ferrygraphql.com/docs/cache-configuration#the-fields-property
• predefined data can be used using optimisticResponse