@graphql-mesh/fusion-execution/esm/extractSubgraph.js

Runtime for Fusion Supergraph

import { buildASTSchema, Kind, parseType, visit, } from 'graphql';
import { getDocumentNodeFromSchema } from '@graphql-tools/utils';
export function extractSubgraphFromFusiongraph(subgraph, fusiongraph) {
    const fusiongraphAst = getDocumentNodeFromSchema(fusiongraph);
    const filterNodeBySubgraph = createFilterNodeBySubgraph(subgraph);
    const filteredAst = visit(fusiongraphAst, {
        Directive(node) {
            const subgraphArgument = node.arguments?.find(argument => argument.name.value === 'subgraph');
            if (subgraphArgument != null &&
                subgraphArgument.value.kind === Kind.STRING &&
                subgraphArgument.value.value !== subgraph) {
                return null;
            }
            return node;
        },
        ObjectTypeDefinition: {
            enter: filterNodeBySubgraph,
        },
        FieldDefinition: {
            enter: filterNodeBySubgraph,
        },
        EnumTypeDefinition: {
            enter: filterNodeBySubgraph,
        },
        EnumValueDefinition: {
            enter: filterNodeBySubgraph,
        },
        InputObjectTypeDefinition: {
            enter: filterNodeBySubgraph,
        },
        ScalarTypeDefinition: {
            enter: filterNodeBySubgraph,
        },
    });
    return buildASTSchema(filteredAst, {
        assumeValid: true,
        assumeValidSDL: true,
    });
}
function createFilterNodeBySubgraph(subgraph) {
    return function filterNodeBySubgraph(node) {
        const sourceDirectives = node.directives?.filter(directive => directive.name.value === 'source');
        const resolverDirectives = node.directives?.filter(directive => directive.name.value === 'resolver');
        for (const sourceDirective of sourceDirectives ?? []) {
            const subgraphArgument = sourceDirective.arguments?.find(argument => argument.name.value === 'subgraph');
            if (subgraphArgument != null &&
                subgraphArgument.value.kind === Kind.STRING &&
                subgraphArgument.value.value === subgraph) {
                let finalNode = node;
                const nameArgument = sourceDirective.arguments?.find(argument => argument.name.value === 'name');
                if (nameArgument?.value.kind === Kind.STRING) {
                    finalNode = {
                        ...node,
                        name: {
                            kind: Kind.NAME,
                            value: nameArgument.value.value,
                        },
                    };
                }
                const typeArgument = sourceDirective.arguments?.find(argument => argument.name.value === 'type');
                if (typeArgument?.value.kind === Kind.STRING) {
                    const typeStr = typeArgument.value.value;
                    finalNode = {
                        ...finalNode,
                        type: parseType(typeStr, { noLocation: true }),
                    };
                }
                return finalNode;
            }
        }
        if (sourceDirectives.length > 0 || resolverDirectives.length > 0) {
            return null;
        }
        return node;
    };
}