graphql/validation/rules/NoFragmentCyclesRule.mjs

A Query Language and Runtime which can target any service.

import { GraphQLError } from "../../error/GraphQLError.mjs";
export function NoFragmentCyclesRule(context) {
    const visitedFrags = new Set();
    const spreadPath = [];
    const spreadPathIndexByName = Object.create(null);
    return {
        OperationDefinition: () => false,
        FragmentDefinition(node) {
            detectCycleRecursive(node);
            return false;
        },
    };
    function detectCycleRecursive(fragment) {
        if (visitedFrags.has(fragment.name.value)) {
            return;
        }
        const fragmentName = fragment.name.value;
        visitedFrags.add(fragmentName);
        const spreadNodes = context.getFragmentSpreads(fragment.selectionSet);
        if (spreadNodes.length === 0) {
            return;
        }
        spreadPathIndexByName[fragmentName] = spreadPath.length;
        for (const spreadNode of spreadNodes) {
            const spreadName = spreadNode.name.value;
            const cycleIndex = spreadPathIndexByName[spreadName];
            spreadPath.push(spreadNode);
            if (cycleIndex === undefined) {
                const spreadFragment = context.getFragment(spreadName);
                if (spreadFragment) {
                    detectCycleRecursive(spreadFragment);
                }
            }
            else {
                const cyclePath = spreadPath.slice(cycleIndex);
                const viaPath = cyclePath
                    .slice(0, -1)
                    .map((s) => '"' + s.name.value + '"')
                    .join(', ');
                context.reportError(new GraphQLError(`Cannot spread fragment "${spreadName}" within itself` +
                    (viaPath !== '' ? ` via ${viaPath}.` : '.'), { nodes: cyclePath }));
            }
            spreadPath.pop();
        }
        spreadPathIndexByName[fragmentName] = undefined;
    }
}
//# sourceMappingURL=NoFragmentCyclesRule.js.map