Unlock the Power of GraphQL: A Beginner’s Guide to Queries

Getting Started with GitHub’s Public API

To demonstrate the power of GraphQL queries, we’ll use GitHub’s public API. Simply head to the GitHub GraphQL Explorer, sign in to your account, and start typing your queries on the left side. Hit play to see the JSON response on the right side. You can also browse through the API documentation on the right side.

Fields: The Building Blocks of GraphQL Queries

A GraphQL query is all about asking for specific fields on objects. These fields are the fundamental components of a query. Let’s write our first query against the GitHub API, requesting the viewer field and its nested name field.

query {
  viewer {
    name
  }
}

Notice how we receive a JSON response with only the requested data.

Arguments: Eliminating Multiple Round-Trips

Arguments can be passed to fields and nested objects in GraphQL, helping to eliminate multiple round-trips to fetch data from the API. Unlike REST, GraphQL allows you to pass arguments to every field and nested object, reducing the need for multiple API fetches. Let’s query the repository field, passing owner and name arguments.

query {
  repository(owner: "github", name: "graphql") {
    name
    description
  }
}

Our JSON response will contain the requested repository information.

Aliases: Querying the Same Field with Multiple Arguments

What if you need to query the same field with different arguments? That’s where aliases come in. Aliases enable you to query the same field with multiple arguments, resolving field conflicts in GraphQL. Let’s add more to our previous query, requesting information on both the Google and Facebook repositories.

query {
  googleRepo: repository(owner: "google", name: "repo") {
    name
    description
  }
  facebookRepo: repository(owner: "facebook", name: "repo") {
    name
    description
  }
}

Fragments: Consolidating Repetitive Fields

Fragments are reusable units that help consolidate repetitive fields in multiple areas of your query. They’re like functions that can be used across multiple queries. Let’s take a look at a query with repetitive fields and refactor it using a fragment.

fragment RepoInfo on Repository {
  name
  description
}

query {
  googleRepo: repository(owner: "google", name: "repo") {
   ...RepoInfo
  }
  facebookRepo: repository(owner: "facebook", name: "repo") {
   ...RepoInfo
  }
}

Notice how our query becomes cleaner and more readable.

Operation Name: Providing Meaningful Names to Your Queries

So far, we’ve been writing queries without providing a name. Providing a meaningful name to your query ensures readability when dealing with multiple queries. Let’s give a name to our query using the query keyword.

query GetRepositories {
  googleRepo: repository(owner: "google", name: "repo") {
   ...RepoInfo
  }
  facebookRepo: repository(owner: "facebook", name: "repo") {
   ...RepoInfo
  }
}

<h2(resources)< h2=””>

For further learning about GraphQL, check out these resources:

• undefined.org/
• undefined.org/learn/
• https://www.graphql.com/

</h2(resources)<>