@theguild/federation-composition/esm/supergraph/validation/rules/field-arguments-of-the-same-type-rule.js

Open Source Composition library for Apollo Federation

import { GraphQLError } from 'graphql';
export function FieldArgumentsOfTheSameTypeRule(context) {
    return {
        ObjectTypeFieldArg(objectTypeState, fieldState, argState) {
            const typeToGraphs = new Map();
            argState.byGraph.forEach((arg, graphName) => {
                const isNonNullable = arg.type.endsWith('!');
                const isNonNullableInSupergraph = argState.type.endsWith('!');
                const isMatchingNonNullablePart = argState.type.replace(/!$/, '') === arg.type.replace(/!$/, '');
                let normalizedOutputType;
                if (isMatchingNonNullablePart) {
                    normalizedOutputType = isNonNullableInSupergraph
                        ? isNonNullable
                            ? arg.type
                            : arg.type + '!'
                        : arg.type;
                }
                else {
                    normalizedOutputType = arg.type;
                }
                const existing = typeToGraphs.get(normalizedOutputType);
                if (existing) {
                    existing.push(graphName);
                }
                else {
                    typeToGraphs.set(normalizedOutputType, [graphName]);
                }
            });
            if (typeToGraphs.size > 1) {
                const groups = Array.from(typeToGraphs.entries()).map(([outputType, graphs]) => {
                    const plural = graphs.length > 1 ? 's' : '';
                    return `type "${outputType}" in subgraph${plural} "${graphs
                        .map(context.graphIdToName)
                        .join('", "')}"`;
                });
                const [first, second, ...rest] = groups;
                context.reportError(new GraphQLError(`Type of argument "${objectTypeState.name}.${fieldState.name}(${argState.name}:)" is incompatible across subgraphs: it has ${first} but ${second}${rest.length ? ` and ${rest.join(' and ')}` : ''}`, {
                    extensions: {
                        code: 'FIELD_ARGUMENT_TYPE_MISMATCH',
                    },
                }));
            }
        },
    };
}