Community Plugin

Gatsby Typescript Plugin

An alternative to the official typescript plugin, with ts-loader & automatic type generation for your graphql queries (using graphql-code-generator)

Installation

yarn add typescript gatsby-plugin-ts

Add this to your gatsby config like any other plugins:

// gatsby-config.js
module.exports = {
  plugins: [
    `gatsby-plugin-ts`,
  ]
}

Unlike the official plugin, you’d have to bring your own tsconfig.json.

# generate a tsconfig if you have none
tsc --init

In order for this plugin to work right, you’d need to set your compile options like the following:

  "compilerOptions": {
    "target": "ES2018",    /* or at least ES2015 */
    "module": "ESNext",    /* or at least ES2015 */
    "lib": ["dom"],             /* <-- required! */
    "jsx": "preserve",          /* <-- required! */
    "moduleResolution": "node", /* <-- required! */

    /* for mixed ts/js codebase */
    "allowJs": true,
    "outDir": "./build"    /* this won't be used by ts-loader */
    /* other options... */
  }

Options

key	default	value
typecheck options
options.tsLoader	`{}`	option to be passed into `ts-loader`. `transpileOnly` is always `true`, since typechecking is handled by `fork-ts-checker-webpack-plugin`. See ts-loader docs for more
options.alwaysCheck	`false`	⚠️deprecated By default type checking is disabled in production mode (during `gatsby build`). Set this to `true` to enable type checking in production as well
options.typeCheck	`true`	Enable / disable type checking with `fork-ts-checker-webpack-plugin`.
options.forkTsCheckerPlugin	`{}`	Options that’ll be passed to `fork-ts-checker-webpack-plugin`. For all options, please see their docs
codegen options
options.codegen	`true`	enable / disable generating definitions for graphql queries
options.documentPaths	[’./src/*/.{ts,tsx}‘, ’./.cache/fragments/.js’, ’./node_modules/gatsby-/*/.js’]	The paths to files containing graphql queries. ⚠️ The default paths will be overwritten by the `documentPaths` you pass in, so please make sure to include all necessary paths ⚠️
options.fileName	`graphql-type.ts`	path to the generated file. By default, it’s placed at the project root directory & it should not be placed into `src`, since this will create an infinite loop
options.codegenDelay	`200`	amount of delay from file change to codegen
options.pluckConfig	{ globalGqlIdentifierName: “graphql”, modules: [ { name: ‘gatsby’, identifier: ‘graphql’ } ] }	options passed to graphql-tag-pluck when extracting queries and fragments from documents
options.failOnError (2.5.0)	`process.env.NODE_ENV === 'production'`	Throw error if the codegen fails. By default only apply to production builds.
options.codegenConfig (^2.7.0)	`{}`	Add config directly to `graphql-codegen`. These key-value config will be applied to every `graphql-codegen` plugins. See graphql-codegen docs on the config field
options.codegenPlugins (^2.7.0)	`[]`	Add additional plugins to `graphql-codegen`. We use the same format as Gatsby’s. See example usage below.
options.additionalSchemas (^2.6.0)	[]	array of additional schemas (other than the schema used by gatsby queries) for which types should be generated for. This is useful when you use client-side queries (e.g. with apollo-client) where you are querying another schema/endpoint

Example Setup

Basic

module.exports = {
  plugins: [
    `gatsby-plugin-ts`,
  ]
}

Custom Output Path

module.exports = {
  plugins: [
    {
      resolve: `gatsby-plugin-ts`,
      options: {
        fileName: `gen/graphql-types.ts`,
      }
    }
  ]
}

I need to change everything

// gatsby-config.js
{
  resolve: `gatsby-plugin-ts`,
  options: {
    tsLoader: {
      logLevel: 'warn',
    },
    forkTsCheckerPlugin: {
      eslint: true,
    },
    fileName: `types/graphql-types.ts`,
    codegen: true,
    codegenDelay: 250,
    typeCheck: false,
    pluckConfig: {
      // this is the default config
      globalGqlIdentifierName: 'graphql',
      modules: [
        { name: 'gatsby', identifier: 'graphql' },
      ],
    },
    additionalSchemas: [
      {
        key: 'example',
        fileName: 'graphql-types-example.ts',
        schema: 'https://example.com/graphql',
        pluckConfig: {
          // config to ensure only queries using the `gql` tag are used for this schema
          globalGqlIdentifierName: 'gql',
          modules: [
            {
              name: 'graphql-tag',
              identifier: 'gql',
            },
          ],
        },
      }
    ],
  },
}

Gatsby files

gatsby-config has to be a .js file
gatsby-node is run directly by node, so it has to be a .js file as well. It is a shame, because in a complicated Gatsby app it is where a lot of logic live & will benefit from ts. As a work around, it can be built with tsc independently, in a script in package.json or somehow in gatsby’s pre-init hook.
Gatsby’s global variable like __PATH_PREFIX__ can be handled by declaring this code somewhere:

// src/global.d.ts
declare const __PATH_PREFIX__: string

Code generation

By default, this plugin will build typing for your queries automatically to graphql-types.d.ts on every edit. Please note that the definition file should not be placed inside src since this triggers a never ending loop during development.

In order to take advantage of the generated code, user needs to name their query:

// src/pages/index.tsx

  export const pageQuery = graphql`
-   query {
+   query BlogIndex {
      site {
        siteMetadata {
          title
        }
      }
  ...

…and import it from the generated type file:

// src/pages/index.tsx

import { BlogIndexQuery } from '../graphqlTypes'

interface IBlogIndexProps {
  data: BlogIndexQuery;
  location: Location;
}

const BlogIndex: React.FC<IBlogIndexProps> = ({ data, location }) => {
  ...
}

Disable type checking in production

Previously this plugin disable type checking in production by default, which can be changed by setting alwaysCheck to true. Since 2.0.0 it no longer does this. If you want to preseve the previous behavior, please set the typeCheck option like below:

{
  resolve: 'gatsby-plugin-ts',
  options: {
    // Disable type checking in production
    typeCheck: process.env.NODE_ENV !== 'production',
  }
}