import * as React from "react"; import { HelmetProvider } from "react-helmet-async"; interface HelmetTestProvider { canUseDOM: boolean; } // The typedef for react-helmet-async doesn't include canUseDOM, even though it's in the docs. // Make TypeScript know it's there. ((HelmetProvider as unknown) as HelmetTestProvider).canUseDOM = false; const ReactHelmetAsyncContextSerializer: jest.SnapshotSerializerPlugin = { test(value: any) { return Boolean( // Does the value exist? value && value.base && value.base.toComponent && value.bodyAttributes && value.bodyAttributes.toComponent && value.htmlAttributes && value.htmlAttributes.toComponent && value.link && value.link.toComponent && value.meta && value.meta.toComponent && value.noscript && value.noscript.toComponent && value.script && value.script.toComponent && value.style && value.style.toComponent && value.title && value.title.toComponent ); }, print(value: any, serialize) { // Recreate head from Helmet data const head = serialize( {value.base.toComponent()} {value.link.toComponent()} {value.meta.toComponent()} {value.noscript.toComponent()} {value.script.toComponent()} {value.style.toComponent()} {value.title.toComponent()} ); // Return recreated head return head; }, }; export = ReactHelmetAsyncContextSerializer;