Tutorials on Apollo

Consider the following code snippet of a React component, <App /> , that... You may have noticed that the data sent back by the mutation provides the user's information in a logIn field, and any data returned from a successful mutation automatically gets added to the local Apollo Client cache. Therefore, why do we have a user state variable when we could just access the user's information via the data field in the mutation result object? For example, like this:

Disclaimer - Please read the first part of this blog post here before proceeding. It walks through the initial steps of building a messages client that fetches messages from a GraphQL API server. If you are already familiar with the basics of Apollo Client, and only want to know how to update a UI optimistically (for mutation results), then download the project from the part-1 branch of the GitHub repository here and follow the directions in the README.md file to set up the project. In the second part of this tutorial series, we will implement the remaining functionality of the messages client: By the end of this tutorial, you will have recreated the optimistic UI found in Messages :

RESTful APIs adhere to a reliable architectural standard for transferring data statelessly over the HTTP protocol. Every endpoint of an API semantically describes how a resource should be created ( POST ), read ( GET ), updated ( PUT / PATCH ), deleted ( DELETE ), etc. Large, data-driven applications consume data from multiple third-party/in-house sources, and each one exposes a unique set of endpoints to manage different resources. Adapting these applications to support a wide range of platforms and device sizes (commonly mobile, desktop and web) may present several problems: Using Facebook's GraphQL query language, the client specifies its exact data requirements to the server via a single endpoint. Establishing a schema (written with the syntax of the GraphQL Schema Definition Language) creates a contract between the client and server that defines what data can be read from and written to the data graph by the client. This data graph centralizes all of the APIs consumed by your application by mapping each field to a resolver that populates it with a value retrieved from an endpoint of one of these APIs, a database, etc. A client can fetch data from a GraphQL server via plain HTTP and then manually update the UI accordingly. However, GraphQL clients such as Apollo Client abstract away the low-level implementation details of these features underneath a declarative API. Built by the Apollo GraphQL team, Apollo Client is an open-source GraphQL client that provides a lot of out-of-the-box functionality for communicating with a GraphQL server:

Apollo is a great interface for fetching and managing data through GraphQL. When we’re building applications with GraphQL, it’s important to manage data effectively to have a smooth development experience. This is where Apollo steps in, and acts as an abstraction layer over GraphQL (which is just a query language) , and provides a robust platform for data fetching. The power of Apollo lies with how much we get out of the box (it’s a lot). We don’t need to do lengthy custom setups or configurations and can get started right away. Here, we’ll be discussing the benefits and usage of Apollo Client with ReactJS, but it’s important to note that most of the same features are also available in Angular and Vue. Before we dive deeper into Apollo, let’s briefly discuss GraphQL.

GraphQL is described as a query language for APIs. It is also considered as an alternative to REST and has been adapted more frequently in the last few years. Do you have a GraphQL endpoint already setup but you are looking forward to gaining some insight on how to gracefully consume this endpoint in a React Native app? Together, let us build a demo app that leverages an integration between Apollo Client, React Native and Expo . Apollo has an entire ecosystem based on to build GraphQL applications. It could be used to develop client-side and server-side apps separately. Apollo has more features and support than its open-source competitors in GraphQL for JavaScript world for now.