GraphQL Scalars TypeDefs Extractor

A utility to manage and generate scalar type definitions from graphql-scalars for seamless integration with GraphQL projects.

Why?

GraphQL Codegen often fails to recognize scalar type definition strings imported from graphql-scalars, leading to errors like:

❯ Generate to src/types/resolvers-types.generated.ts
  ✖
    Failed to load schema from ./src/**/*.ts:
    Unknown type: "Date".
    Error: Unknown type: "Date".

This tool automatically generates a reusable type definition from graphql-scalars, ensuring that codegen recognizes the custom scalar types.

It generates scalar type definitions in either GraphQL SDL format or as a gql-tagged (from graphql-tag) GraphQL template literal, depending on the file extension specified in the output option.

Installation

npm install graphql-scalars-type-defs-extractor
# or
yarn add graphql-scalars-type-defs-extractor

Usage

CLI

# Output to a GraphQL file
npx graphql-scalars-type-defs-extractor -o ./scalar-types.graphql

# Output to a TypeScript file
npx graphql-scalars-type-defs-extractor -o ./scalar-types.ts

# Output to a JavaScript file
npx graphql-scalars-type-defs-extractor -o ./scalar-types.js

# Output specific scalar types (e.g., DateTime, Email)
npx graphql-scalars-type-defs-extractor -s DateTime Email

# Output with verbose logging
npx graphql-scalars-type-defs-extractor -o ./scalar-types.graphql -v

# Example combining options
npx graphql-scalars-type-defs-extractor -o ./types/scalars.ts -s DateTime Email -v

CLI Options

• -o, --output: Specify the output file path (e.g., ./types/scalars.graphql or ./types/scalars.ts). Defaults to scalar-types.graphql.
• -s, --scalars: List of specific scalar types to extract. If not provided, all scalars will be extracted.
• -v, --verbose: Enable verbose logging to see detailed output during extraction.
• -h, --help: Show help information.

In Codegen Configuration

import { extractScalarTypeDefs } from "graphql-scalars-type-defs-extractor";

const scalarTypesPath = extractScalarTypeDefs({
  output: "scalar-types.graphql",
  scalars: ["DateTime", "Email"],
});

const config = {
  schema: [
    "./src/**/*.ts",
    scalarTypesPath, // Add only if the generated scalar types file is not already covered by the schema's watch pattern
  ],
  generates: {
    "src/types/resolvers-types.generated.ts": {
      plugins: ["typescript", "typescript-resolvers"],
    },
  },
};

export default config;

extractScalarTypeDefs's Parameters

• options: An object with the following properties:
  • output: Custom file path (.graphql, .ts, .js). Defaults to scalar-types.graphql.
  • scalars: An optional array of specific scalar types to extract (e.g., ["DateTime", "Email"]). If not provided, all scalars will be extracted.
  • verbose: A boolean flag to enable verbose logging (default is false).

Compatibility

• Requires graphql-scalars and graphql-tag (for .ts/.js output)

License

MIT