@manifoldco/graphql-gen

⚛️ graphql-gen

Node client for generating crude GraphQL specs from Swagger OpenAPI.

💅 Prettifies output via Prettier.

Support

GraphQL Features
Enum	✅
ID	✅
Union (oneOf)	✅
Non-nullable	✅
Primitives (string, boolean, number)	✅
Query	🚫
Mutation	🚫

To compare actual generated output, see the example folder.

Usage

CLI

npx @manifoldco/graphql-gen schema.yaml --output schema.graphql

# 🚀 schema.yaml -> schema.graphql [2ms]

This will save a schema.graphql file in the current folder. The CLI can accept YAML or JSON for the input file.

Node

npm i --save-dev @manifoldco/graphql-gen

const graphqlGen = require('@manifoldco/graphql-gen');

graphqlGen(spec, [options]);

spec must be in JSON format. For an example of converting YAML to JSON, see the generate.js script.

Options

Name	Default	Description
output	(stdout)	Where should the output file be saved?
swagger	2	Which Swagger version to use. Currently only supports 2.

FAQ

Why does this exist apart from yarax/swagger-to-graphql ?

That didn’t work for our Swagger 2.0 specs 🤷. While normally a PR is the best course of action, this repo exists because it was less effort to build something that works for us than rewrite a popular library (it wasn’t a quick fix).

Why aren’t Queries and Mutations generated from the OpenAPI spec?

While it’s possible to generate something from OpenAPI, it’s intentionally omitted from autogeneration here. Queries and Mutations are best left up to humans, so you can determine what developers should access, and how. Ultimately generating these will always fall short of how real humans could—and should—use your GraphQL endpoint.

Notes

GraphQL is a spec, just like OpenAPI. For this reason, automatic generation isn’t ideal long-term. This library should probably be used as a first-pass to migrate an OpenAPI endpoint to GraphQL. This can generate types, but can’t intelligently generate the best queries and mutations for your specific endpoint.

A common example of this: Swagger has a concept of format: datetime. GraphQL cares about this, but doesn’t assume the formatting. Is this UNIX time? ISO? Are there timezones? Types can be so much more descriptive than mere string or int, and GraphQL gives you the tools to declare this yourself.