relay-compiler-language-typescript

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As per @orta’s comment, we should add schema comments as documentation to the type definitions.

Not quite figured this, looking like the details come though on the original createVisitor callbacks, but loses the description down the line. For now, I have a pretty solid test that should be green when it all works.

import { GraphQLSchema, GraphQLObjectType, GraphQLString, GraphQLID, GraphQLInterfaceType, GraphQLNonNull } from "graphql";
import {GraphQLCompilerContext, IRTransforms, transformASTSchema} from 'relay-compiler'
import * as parseGraphQLText from 'relay-test-utils/lib/parseGraphQLText'
import * as TypeScriptGenerator from '../src/TypeScriptGenerator'

const DogNameDescription = "Ideally short and sweet"

export const NodeInterface = new GraphQLInterfaceType({
  name: "Node",
  description: "An object with a Globally Unique ID",
  fields: () => ({
    id: {
      type: new GraphQLNonNull(GraphQLID),
      description: "The ID of the object.",
    },
  }),
})

const DogType = new GraphQLObjectType({
  name: 'Dog',
  fields: {
    id: { type:  new GraphQLNonNull(GraphQLID) },
    name: { type: GraphQLString, description: DogNameDescription }
  },
  interfaces: [NodeInterface],
})

const schema = new GraphQLSchema({
  query: new GraphQLObjectType({
    name: 'Query',
    fields: {
      doggo: {
        type: DogType,
        args: {
          id: { type: new GraphQLNonNull(GraphQLID) }
        }
      }
    }
  })
})

test("handles adding the comment on a field", () => {
  const text = `
  fragment HandlesCommentsFragment on Node {
    id
    ... on Dog {
      name
    } 
  }
  `

  const {definitions} = parseGraphQLText(schema, text);
  const tsInterface = new GraphQLCompilerContext(schema, schema)
    .addAll(definitions)
    .applyTransforms(TypeScriptGenerator.transforms)
    .documents()
    .map(doc =>
      TypeScriptGenerator.generate(doc, {
        customScalars: {},
        enumsHasteModule: null,
        existingFragmentNames: new Set(['PhotoFragment']),
        inputFieldWhiteList: [],
        relayRuntimeModule: 'relay-runtime',
        useHaste: true,
      }),
    )
    .join('\n\n');

    expect(tsInterface).toContain(DogNameDescription)
})

Without having looked too much into it. I think some changes to the relay code might be needed to make this work.

The way I see it, the IR representation should contain the comments. See the TS type definitions here (copy/pasted and adapted from flow code from the relay code): https://github.com/relay-tools/relay-compiler-language-typescript/blob/master/types/graphql-compiler/core/GraphQLIR.d.ts.

But perhaps some dialog with the Relay team is in order wrt. solving this.