![graphql fragments graphql fragments](https://miro.medium.com/max/3000/0*VYR2_E31i-t8U42v.gif)
Relay defaults to the performant and defensive pattern. With this structure: Its hard to over-fetch or under-fetch data, because each component declares exactly the data it needs. Let’s see a first example of such a query. Relay composes fragments from multiple components into optimized and efficient batches to reduce round-trips to the server. The server responds to a query by providing a JSON object. You send a query to that endpoint by using a special Query Language syntax. GraphQL exposes a single endpoint from your server. Although this approach is a big step in the right direction and I think this can work very well if you don’t plan to ever use anything other. This makes it much easier to detect and remove obsolete fields. That’s when I discovered it’s a game changer in many aspects. As you can see in the quite complex example above, by using fragments we manage to define fields only in components where they are used. I’ve first been in touch with GraphQL when GitHub decided to implement the v4 of their API using that technology, and I joined their beta program. Many big companies are adopting GraphQL beside Facebook, including GitHub, Pinterest, Twitter, Sky, The New York Times, Shopify, Yelp and thousands many other. GraphQL was developed at Facebook, like many of the technologies that are shaking the JavaScript world lately, like React and React Native, and it was publicly launched in 2015 - although Facebook used it internally for a few years before. It creates a whole new dimension for API design. It is a methodology that directly competes with REST ( REpresentational State Transfer) APIs, much like REST competed with SOAP at first.Īnd as we’ll see, it’s very different from REST. It’s not tied to a specific technology, but you can implement it in any language. It’s a query language, and a set of server-side runtimes (implemented in various backend languages) for executing queries. GraphQL is the new frontier in APIs ( Application Programming Interfaces) design, and in how we build and consume them. Specifying a default value for a variable.This article explores the pros and cons and, prompted by the request for feedback from the GraphQL Working Group, suggests a few good use cases for them. As an example we could have: FurnitureĪs you can see our Furniture category is the parent and has children ( Dining Room and Living Room) and those each have children. Examining the proposal on allowing recursions in fragments leads me to ask some fundamental questions, including whether the GraphQL spec should allow recursive fragments. GraphQL Fragments for Recursive QueryĪs per our example we have a GraphQL object definition called Category and our category object can have children categories and those children could have children. Fragments allow you to construct sets of repeatable fields, and then include them in queries where you need to. So how does one recursively call a GraphQL query if the query object is hierarchal and contains children? We do have to “plan” how deep our query will go but we can save ourselves a lot of time by using GraphQL Fragments. In this case, people is of type Person and we want to select the firstName and lastName fields from people (id: '7').
![graphql fragments graphql fragments](https://experienceleague.adobe.com/docs/experience-manager-cloud-service/assets/cfm-graphqlapi-02.png)
Its important to note that the component after the on clause is designated for the type we are selecting from. If this is used, document nodes are generated on client side i.e. A GraphQL fragment is a shared piece of query logic. Declares how DocumentNode are created: graphQLTag: graphql-tag or other modules (check gqlImport) will be used to generate document nodes. Otherwise an operation could infinitely spread or infinitely execute on cycles in the underlying data. Changes the GraphQL fragments variables suffix. The graph of fragment spreads must not form any cycles including spreading itself. Imagine now that your integration needs to process requests and that the logic to process requests of category Incident is different from the logic to process requests of category RFC.
#Graphql fragments how to
In the previous exercises you have learned how to add filters to GraphQL queries. It’s not possible to write a recursive query of unlimited depth. 4me GraphQL - Aliases and Fragments Aliases.
#Graphql fragments code
This, combined with GraphQLs support for fragments, allows you to split your queries up in such a way that the various fields fetched by the queries are located right alongside the code that uses the field. We discovered that GraphQL does not allow for recursive calls as per the specs. A key advantage of GraphQL is the tree-like nature of the response data, which in many cases mirrors your rendered component hierarchy. The use case was for a hierarchy of product categories on our site where a category can be a parent and have children, and the children could have children etc. We recently ran into a scenario where we wanted to create a GraphQL query that could recursively call children of a definition type.