@theguild/federation-composition/esm/utils/link/index.js

Open Source Composition library for Apollo Federation

import { FederatedLink } from './link.js';
export const FEDERATION_V1 = Symbol('Federation_V1');
export function extractLinkImplementations(typeDefs) {
    const links = FederatedLink.fromTypedefs(typeDefs);
    const linkByIdentity = Object.fromEntries(links.map(l => [l.identity, l]));
    const supportsFederationV2 = Object.keys(linkByIdentity).length > 0;
    return {
        links,
        resolveImportName: (identity, name) => {
            const matchingLink = linkByIdentity[identity];
            if (!matchingLink) {
                return name.startsWith('@') ? name.substring(1) : name;
            }
            return matchingLink.resolveImportName(name);
        },
        matchesImplementation: (identity, version) => {
            if (version === FEDERATION_V1) {
                return !supportsFederationV2;
            }
            const matchingLink = linkByIdentity[identity];
            if (!matchingLink) {
                return false;
            }
            if (typeof version === 'string') {
                return matchingLink.supports(version);
            }
            if (version === null) {
                return matchingLink.supports(version);
            }
            return matchingLink.supports(version.major, version.minor);
        },
    };
}