resthall.blogg.se - Graphql fragments

#Graphql fragments how to#

We don't want to be grabbing a bunch of extraneous data all the time, but maintaining a fragment is pretty cool. We want to just ask for the fields we need. And this way, we're still adhering to the principles of GraphQL's declarative query syntax. I would maybe call this LiftDetails instead. So, the fragment is very useful in a case like this, but I would caution you, that make sure you really need all these fields when you're using them. I can send the exact same query and get back the exact same fields.

What's really cool about this, and the reason I said this was for composition, is let's say I wanted to send a query for all lifts, dot dot dot AllFields.

So, I'll use the spread syntax, dot dot dot, and I'll push in AllFields. So here, we'll add an id, a name, a status, a capacity, a night, an elevationGain, all these different fields, right? And now what I can do is I can remove name and status from our Lift query, and I can push them in right here. So, we couldn't create a fragment of trail and lift fields together, instead I would have to create this with a single fragment on the Lift type. First thing I'll say, is fragment AllFields, and when I create the fragment, I need to create it on a specific type. So, I'll show you a couple of uses for it. And so that I would say there is no operation for that, but there's a way that we can do this with a fragment that may be useful. So, usually at this point in the class, someone asked me, how do I do like a star query? Like give me all the fields please. So, we're familiar with this syntax, but let's say I wanted to reuse some fields. We'll take in the id of panorama and we'll get the name and the status. Then, you pass your newly configured cache to ApolloClient to complete the process.- Another nice thing to know about the GraphQL query language is that we can take advantage of GraphQL fragments for composition. Use possibleTypes.json to configure your cache during construction.Or use the plugin fragment-matcher for graphql-codegen and configure it for apollo client 3.

#Graphql fragments how to#

Read the documentation about how to extract possibleTypes automatically using an introspection query.

Query your server / schema to obtain the necessary information about unions and interfaces and write it to a file.

We recommend setting up a build step that extracts the necessary information from the schema into a JSON file, where it can be imported from when constructing the cache. The section below explains how to pass the necessary schema knowledge to the Apollo Client cache so unions and interfaces can be accurately matched and results validated before writing them into the store. To inform the cache store about these polymorphic relationships, you need to pass possibleTypes option to InMemor圜ache below. This works in most cases, but it also means that Apollo Client cannot check the server response for you, and it cannot tell you when you're manually writing invalid data into the store using update, updateQuery, writeQuery, etc. By default, Apollo Client's cache will use a heuristic fragment matcher, which assumes that a fragment matched if the result included all the fields in its selection set, and didn't match when any field was missing. Both Jedi and Droid are possible concrete types of Character, but on the client there is no way to know that without having some information about the schema. In the query above, allPeople returns a result of type Character.