@theguild/federation-composition/esm/supergraph/validation/rules/required-query-rule.js

Open Source Composition library for Apollo Federation

import { GraphQLError } from "graphql";
export function RequiredQueryRule(context) {
    if (Array.from(context.subgraphStates.values()).every((subgraph) => typeof subgraph.schema.queryType === "undefined")) {
        context.reportError(new GraphQLError(`No queries found in any subgraph: a supergraph must have a query root type.`, {
            extensions: {
                code: "NO_QUERIES",
            },
        }));
    }
}