import { Callout } from '@theguild/components'

Programmatic Usage

GraphQL Code Generator also provides a complete programmatic API.

The programmatic API can be used if you need to customize the execution flow or write a tool that uses the codegen.

Basic Programmatic Usage

In order to use the programmatic API, start by importing codegen from @graphql-codegen/core:

import { codegen } from '@graphql-codegen/core'

Then, create a configuration object (complete signature):

import fs from 'node:fs'
import path from 'node:path'
import { buildSchema, printSchema, parse, GraphQLSchema } from 'graphql'
import * as typescriptPlugin from '@graphql-codegen/typescript'

const schema: GraphQLSchema = buildSchema(`type A { name: String }`)
const outputFile = 'relative/pathTo/filename.ts'
const config = {
  documents: [],
  config: {},
  // used by a plugin internally, although the 'typescript' plugin currently
  // returns the string output, rather than writing to a file
  filename: outputFile,
  schema: parse(printSchema(schema)),
  plugins: [
    // Each plugin should be an object
    {
      typescript: {} // Here you can pass configuration to the plugin
    }
  ],
  pluginMap: {
    typescript: typescriptPlugin
  }
}

<Callout> The `schema` field be a valid `GraphQLSchema` object. If you need to load your GraphQL schema from an external source (file, URL), you can use `loadSchema` from `@graphql-tools/load`. </Callout>

Notice that a plugin name key in pluginMap and plugins must match to identify a plugin and its configuration.

<Callout>You need to import the plugin in your favorite way; you can also use await import to lazy load it.</Callout>

Then, provide the config object to codegen:

const output = await codegen(config)
await fs.writeFile(path.join(__dirname, outputFile), output, 'utf8')
console.log('Outputs generated!')

<Callout> We are using this API in the live demo on the GraphQL Code Generator website. [The code is here](https://github.com/dotansimha/graphql-code-generator/blob/master/website/src/components/live-demo/generate.ts). </Callout> <Callout> **Loading schema and documents**

You can use one of the tools from @graphql-tools for file loading, schema merging, transformations and more.

</Callout>

Using the CLI instead of `core`

If you wish to have the benefits that cli package has (like loading schema and document files, parsing endpoints and more), you can use require() (or import) for @graphql-codegen/cli directly with Node.JS:

import { generate } from '@graphql-codegen/cli'

async function doSomething() {
  const generatedFiles = await generate(
    {
      schema: 'http://127.0.0.1:3000/graphql',
      documents: './src/**/*.graphql',
      generates: {
        [process.cwd() + '/models/types.d.ts']: {
          plugins: ['typescript']
        }
      }
    },
    true
  )
}

The return value should be of type Promise<FileOutput[]>.

<Callout type="warning"> This usage will not work in a browser environment because the `cli` package depends on Node.js internals and the file system. </Callout>

Programmatic Usage

Programmatic Usage

Basic Programmatic Usage

Using the CLI instead of core

Using the CLI instead of `core`