graphile-build/node8plus/plugins/QueryPlugin.js.flow

Build a GraphQL schema from plugins

// @flow
import type { Plugin, Build } from "../SchemaBuilder";

export type BuildExtensionQuery = {|
  $$isQuery: Symbol,
|};

export default (async function QueryPlugin(builder) {
  builder.hook(
    "build",
    (build: Build): Build & BuildExtensionQuery =>
      build.extend(
        build,
        {
          $$isQuery: Symbol("isQuery"),
        },
        `Extending Build`
      ),
    ["Query"]
  );
  builder.hook(
    "GraphQLSchema",
    (schema: {}, build) => {
      const {
        $$isQuery,
        newWithHooks,
        extend,
        graphql: { GraphQLObjectType, GraphQLNonNull },
        inflection,
      } = build;
      const queryType = newWithHooks(
        GraphQLObjectType,
        {
          description: build.wrapDescription(
            "The root query type which gives access points into the data universe.",
            "type"
          ),
          name: inflection.builtin("Query"),
          isTypeOf: (value, _context, info) =>
            info.parentType == null || value === $$isQuery,
          fields: ({ Self }) => ({
            query: {
              description: build.wrapDescription(
                "Exposes the root query type nested one level down. This is helpful for Relay 1 which can only query top level fields if they are in a particular form.",
                "field"
              ),
              type: new GraphQLNonNull(Self),
              resolve() {
                return $$isQuery;
              },
            },
          }),
        },
        {
          __origin: `graphile-build built-in (root query type)`,
          isRootQuery: true,
        },
        true
      );
      if (queryType) {
        return extend(
          schema,
          {
            query: queryType,
          },
          `Adding 'query' type to Schema`
        );
      } else {
        return schema;
      }
    },
    ["Query"]
  );
}: Plugin);