README.md

This project integrates GraphQL and ESLint, for a better developer experience.

Created and maintained by The Guild

Key Features

• 🚀 Integrates with ESLint core (as a ESTree parser)
• 🚀 Works on .graphql files, gql usages and /* GraphQL */ magic comments
• 🚀 Lints both GraphQL schema and GraphQL operations
• 🚀 Extended type info for more advanced usages
• 🚀 Supports ESLint directives (for example: eslint-disable-next-line)
• 🚀 Easily extendable - supports custom rules based on GraphQL's AST and ESLint API
• 🚀 Validates, lints, prettifies and checks for best practices across GraphQL schema and GraphQL operations
• 🚀 Integrates with graphql-config
• 🚀 Integrates and visualizes lint issues in popular IDEs (VSCode / WebStorm)

Special thanks to ilyavolodin for his work on a similar project!

Getting Started

• Introducing GraphQL-ESLint! @ the-guild.dev

Installation

Start by installing the plugin package, which includes everything you need:

yarn add -D @graphql-eslint/eslint-plugin

Or, with NPM:

npm install --save-dev @graphql-eslint/eslint-plugin

Make sure you have graphql dependency in your project.

Configuration

To get started, define an override in your ESLint config to apply this plugin to .graphql files. Add the rules you want applied.

🚨 Important! This step is necessary even if you are declaring operations and/or schema in code files.

{
  "overrides": [
    {
      "files": ["*.graphql"],
      "parser": "@graphql-eslint/eslint-plugin",
      "plugins": ["@graphql-eslint"],
      "rules": {
        "@graphql-eslint/known-type-names": "error"
      }
    }
  ]
}

If your GraphQL definitions are defined only in .graphql files, and you're only using rules that apply to individual files, you should be good to go 👍. If you would like use a remote schema or use rules that apply across the entire collection of definitions at once, see here.

Apply this plugin to GraphQL definitions defined in code files

If you are defining GraphQL schema or GraphQL operations in code files, you'll want to define an additional override to extend the functionality of this plugin to the schema and operations in those files.

{
  "overrides": [
+   {
+     "files": ["*.js"],
+     "processor": "@graphql-eslint/graphql"
+   },
    {
      "files": ["*.graphql"],
      "parser": "@graphql-eslint/eslint-plugin",
      "plugins": ["@graphql-eslint"],
      "rules": {
        "@graphql-eslint/known-type-names": "error"
      }
    }
  ]
}

Under the hood, specifying the @graphql-eslint/graphql processor for code files will cause graphql-eslint/graphql to extract the schema and operation definitions from these files into virtual GraphQL documents with .graphql extensions. This will allow the overrides you've defined for .graphql files, via "files": ["*.graphql"], to get applied to the definitions defined in your code files.

Extended linting rules with GraphQL Schema

Some rules require an understanding of the entire schema at once. For example, no-unreachable-types checks that all types are reachable by root-level fields.

To use these rules, you'll need to tell ESLint how to identify the entire set of schema definitions.

If you are using graphql-config, you are good to go. graphql-eslint integrates with it automatically and will use it to load your schema!

Alternatively, you can define parserOptions.schema in the *.graphql override in your ESLint config.

The parser allows you to specify a json file / graphql files(s) / url / raw string to locate your schema (We are using graphql-tools to do that). Just add parserOptions.schema to your configuration file:

{
  "files": ["*.graphql"],
  "parser": "@graphql-eslint/eslint-plugin",
  "plugins": ["@graphql-eslint"],
  "rules": {
    "@graphql-eslint/no-unreachable-types": "error"
  },
+ "parserOptions": {
+   "schema": "./schema.graphql"
+ }
}

You can find a complete documentation of the parserOptions here.

Some rules require type information to operate, it's marked in the docs for each rule!

Extended linting rules with siblings operations

While implementing this tool, we had to find solutions for a better integration of the GraphQL ecosystem and ESLint core.

GraphQL operations can be distributed across many files, while ESLint operates on one file at a time. If you are using GraphQL fragments in separate files, some rules might yield incorrect results, due the missing information.

To workaround that, we allow you to provide additional information on your GraphQL operations, making it available for rules while doing the actual linting.

To provide that, we are using graphql-tools loaders to load your sibling operations and fragments, just specify a glob expression(s) that points to your code/.graphql files:

{
  "files": ["*.graphql"],
  "parser": "@graphql-eslint/eslint-plugin",
  "plugins": ["@graphql-eslint"],
  "rules": {
    "@graphql-eslint/unique-operation-name": "error"
  },
  "parserOptions": {
+   "operations": "./src/**/*.graphql",
    "schema": "./schema.graphql"
  }
}

VSCode Integration

By default, ESLint VSCode plugin will not lint files with extensions other than js, jsx, ts and tsx.

In order to enable it processing other extensions, add the following section in settings.json or workspace configuration.

{
  "eslint.validate": ["javascript", "javascriptreact", "typescript", "typescriptreact", "graphql"]
}

Currently, you also need a GraphQL IDE extension for syntax highlighting installed (which may potentially have its own linting) - for example GraphQL (by GraphQL Foundation).

Disabling Rules

The graphql-eslint parser looks for GraphQL comments syntax (marked with #) and will send it to ESLint as directives. That means, you can use ESLint directives syntax to hint ESLint, just like in any other type of files.

To disable ESLint for a specific line, you can do:

# eslint-disable-next-line
type Query {
  foo: String!
}

You can also specify specific rules to disable, apply it over the entire file, eslint-disable-next-line or current eslint-disable-line.

You can find a list of ESLint directives here.

Available Rules

You can find a complete list of all available rules here.

Deprecated Rules

See docs/deprecated-rules.md.

Available Configs

Name	Description
schema-recommended	enables recommended rules for schema (SDL) development
schema-all	enables all rules for schema (SDL) development, except for those that require parserOptions.operations option
operations-recommended	enables recommended rules for consuming GraphQL (operations) development
operations-all	enables all rules for consuming GraphQL (operations) development
relay	enables rules from Relay specification for schema (SDL) development

If you are in a project that develops the GraphQL schema, you'll need schema rules.

If you are in a project that develops GraphQL operations (query/mutation/subscription), you'll need operations rules.

If you are in a monorepo project, you probably need both sets of rules.

Config usage

For example, to enable the schema-recommended config, enable it in your .eslintrc file with the extends option:

All configs under the hood set parser as @graphql-eslint/eslint-plugin and add @graphql-eslint to plugins array, so you don't need to specify them.

{
  "overrides": [
    {
      "files": ["*.js"],
      "processor": "@graphql-eslint/graphql"
    },
    {
      "files": ["*.graphql"],
-     "parser": "@graphql-eslint/eslint-plugin",
-     "plugins": ["@graphql-eslint"],
+     "extends": "plugin:@graphql-eslint/schema-recommended"
    }
  ]
}

prettier rule

eslint-plugin-prettier supports .graphql files. You need to do the following:

module.exports = {
  overrides: [
    {
      files: ['*.js'],
      processor: '@graphql-eslint/graphql',
      extends: ['plugin:prettier/recommended']
    },
    {
      files: ['*.graphql'],
      parser: '@graphql-eslint/eslint-plugin',
      plugins: ['@graphql-eslint'],
      rules: {
        'prettier/prettier': 'error'
      }
    },
    // the following is required for `eslint-plugin-prettier@<=3.4.0` temporarily
    // after https://github.com/prettier/eslint-plugin-prettier/pull/415
    // been merged and released, it can be deleted safely
    {
      files: ['*.js/*.graphql'],
      rules: {
        'prettier/prettier': 'off'
      }
    }
  ]
}

You can take examples/prettier as example.

It could be better to remove the unnecessary *.js/*.graphql override setting if prettier/eslint-plugin-prettier#415 will be merged and released.

Please help to vote up if you want to speed up the progress.

Further Reading

If you wish to learn more about this project, how the parser works, how to add custom rules and more please refer to the below links:

• Writing Custom Rules
• How the parser works?
• parserOptions

Contributions

Contributions, issues and feature requests are very welcome. If you are using this package and fixed a bug for yourself, please consider submitting a PR!

And if this is your first time contributing to this project, please do read our Contributor Workflow Guide before you get started off.

Code of Conduct

Help us keep GraphQL ESLint open and inclusive. Please read and follow our Code of Conduct as adopted from Contributor Covenant.

License

Released under the MIT license.