GraphQL at Scale: A Closer Look at urql
As someone who has worked extensively with GraphQL, I’ve had the opportunity to explore various libraries that make working with GraphQL a breeze. Recently, I came across urql, a lightweight and extensible GraphQL client for React that caught my attention. In this article, we’ll delve into the world of GraphQL, explore the benefits of using a library like urql, and compare it to the popular Apollo library.
What is GraphQL?
GraphQL is a query language that allows clients to request exactly what they need from a server, reducing the amount of data transferred and improving performance. It’s like sending a string with all the keys of a JSON object that the server should populate for you. GraphQL has three operation types: query, mutation, and subscription. Queries are for requesting data, mutations are for changing data, and subscriptions are for real-time data.
Why Do We Need a Library?
While you can use simple fetch calls to interact with a GraphQL server, a library like urql provides additional benefits such as client-side caching and utilities for data fetching. Caching is particularly important, as it allows you to store frequently accessed data locally, reducing the number of requests made to the server.
Using urql
urql is designed to make working with GraphQL on the client-side as simple as possible. It provides a lightweight and extensible solution that’s easy to set up and use. With urql, you can use a component API or a Hooks API to interact with your GraphQL server. The component API is based on render props and consists of <Query>, <Mutation>, and <Subscription> components. The Hooks API, on the other hand, consists of useQuery, useMutation, and useSubscription hooks.
Caching in urql
urql’s caching mechanism is simple yet effective. It caches results from queries by the exact query and any variables, mapped to the result of that query. When a mutation is made, urql invalidates any cached data containing the types included in the mutation response. This ensures that your data remains up-to-date and in sync with the server.
Mutating Data with urql
Mutating data with urql is straightforward. You can use the Hooks API to create mutations and update your data. However, it’s essential to be mindful of what your GraphQL server returns, as this can affect the caching mechanism. For example, if your server returns an empty array when removing the last item from a list, urql may not invalidate the proper query caches, leading to data inconsistencies.
Differences Between urql and Apollo
Apollo is a popular GraphQL library that’s widely used in the industry. While both urql and Apollo provide similar functionality, they differ in their philosophies and approaches. urql is designed to be lightweight and extensible, trusting the open-source community to solve niche problems. Apollo, on the other hand, is a company that aims to provide a comprehensive solution for every problem.
API Comparison
The APIs of urql and Apollo are similar, with both providing <Query>, <Mutation>, and <Subscription> components, as well as Hooks APIs. However, Apollo has a more extensive API that includes direct access to the cache, which can be useful in certain scenarios.
Caching Strategies
The caching strategies of urql and Apollo differ significantly. urql caches on the query level, whereas Apollo normalizes its cache, caching every item returned from GraphQL by its id and type. This approach allows Apollo to handle complex caching scenarios, but it can also lead to tradeoffs, such as updating multiple lists when a single item is mutated.
Conclusion
In conclusion, urql is a promising GraphQL library that provides a lightweight and extensible solution for working with GraphQL on the client-side. While it may lack some features out of the box, its simplicity and ease of use make it an attractive option for developers. If you’re looking for a simple library to get started with GraphQL, I would definitely recommend giving urql a shot.