add support for previewing pages

web/codegen.ts

@@ -3,8 +3,14 @@ import { CodegenConfig } from "@graphql-codegen/cli";
 import { loadEnvConfig } from "@next/env";
 loadEnvConfig(process.cwd());
 
+const wagtailBaseUrl = process.env.WAGTAIL_BASE_URL;
+if (!wagtailBaseUrl) {
+  throw new Error("WAGTAIL_BASE_URL is not set");
+}
+const graphqlEndpoint = `${wagtailBaseUrl.replace(/\/$/, "")}/api/graphql/`;
+
 const config: CodegenConfig = {
-  schema: process.env.GRAPHQL_ENDPOINT,
+  schema: graphqlEndpoint,
   documents: ["src/**/*.tsx", "src/**/*.ts"],
   ignoreNoDocuments: true, // for better experience with the watcher
   generates: {