[fix] page chunk for root level catch-all is served incorrectly to client

lib/constants/regex.js

@@ -0,0 +1,9 @@
+const CATCH_ALL_REGEX = /\/\[\.{3}(.*)\](.json)?$/;
+const OPTIONAL_CATCH_ALL_REGEX = /\/\[{2}\.{3}(.*)\]{2}(.json)?$/;
+const DYNAMIC_PARAMETER_REGEX = /\/\[(.*?)\]/g;
+
+module.exports = {
+  CATCH_ALL_REGEX,
+  OPTIONAL_CATCH_ALL_REGEX,
+  DYNAMIC_PARAMETER_REGEX,
+};

lib/helpers/getNetlifyRoutes.js

@@ -1,9 +1,11 @@
 // Adapted from @sls-next/lambda-at-edge (v1.2.0-alpha.3)
 // See: https://github.com/danielcondemarin/serverless-next.js/blob/57142970b08e6bc3faf0fc70749b3b0501ad7869/packages/lambda-at-edge/src/lib/expressifyDynamicRoute.ts#L4
 
-const CATCH_ALL_REGEX = /\/\[\.{3}(.*)\](.json)?$/;
-const OPTIONAL_CATCH_ALL_REGEX = /\/\[{2}\.{3}(.*)\]{2}(.json)?$/;
-const DYNAMIC_PARAMETER_REGEX = /\/\[(.*?)\]/g;
+const {
+  CATCH_ALL_REGEX,
+  OPTIONAL_CATCH_ALL_REGEX,
+  DYNAMIC_PARAMETER_REGEX,
+} = require("../constants/regex");
 
 // Convert dynamic NextJS routes into their Netlify-equivalent
 // Note that file endings (.json) must be removed for catch-all and optional

lib/helpers/isRootCatchAllRedirect.js

@@ -0,0 +1,5 @@
+// Return true if the redirect is a root level catch-all
+// (e.g., /[[...slug]])
+const isRootCatchAllRedirect = (redirect) => redirect.startsWith("/*");
+
+module.exports = isRootCatchAllRedirect;

lib/steps/setupRedirects.js

@@ -4,6 +4,7 @@ const { logTitle, logItem } = require("../helpers/logger");
 const { NETLIFY_PUBLISH_PATH, CUSTOM_REDIRECTS_PATH } = require("../config");
 const getSortedRoutes = require("../helpers/getSortedRoutes");
 const getNetlifyRoutes = require("../helpers/getNetlifyRoutes");
+const isRootCatchAllRedirect = require("../helpers/isRootCatchAllRedirect");
 
 // Setup _redirects file that routes all requests to the appropriate location,
 // such as one of the Netlify functions or one of the static files.
@@ -14,7 +15,7 @@ const setupRedirects = () => {
   const redirects = [];
   if (existsSync(CUSTOM_REDIRECTS_PATH)) {
     logItem("# Prepending custom redirects");
-    redirects.push(readFileSync(CUSTOM_REDIRECTS_PATH));
+    redirects.push(readFileSync(CUSTOM_REDIRECTS_PATH, "utf8"));
   }
 
   // Collect redirects for NextJS pages
@@ -50,6 +51,16 @@ const setupRedirects = () => {
     });
   });
 
+  // This takes care of this issue: https://github.com/netlify/next-on-netlify/issues/43
+  // where the page chunk for a root level catch-all is served incorrectly to the client.
+  // NOTE: Netlify is also investigating this issue internally.
+  const hasRootCatchAll = redirects.some(isRootCatchAllRedirect);
+  if (hasRootCatchAll) {
+    const rootCatchAllIndex = redirects.findIndex(isRootCatchAllRedirect);
+    // Add general "no-op" redirect before the root catch-all redirect
+    redirects.splice(rootCatchAllIndex, 0, "/_next/*  /_next/:splat  200");
+  }
+
   // Write redirects to _redirects file
   writeFileSync(join(NETLIFY_PUBLISH_PATH, "_redirects"), redirects.join("\n"));
 };

package.json

@@ -56,7 +56,7 @@
   },
   "husky": {
     "hooks": {
-      "pre-commit": "npm run format"
+      "pre-commit": "prettier --check ."
     }
   }
 }

tests/__snapshots__/optionalCatchAll.test.js.snap

@@ -7,5 +7,6 @@ exports[`Routing creates Netlify redirects 1`] = `
 /_next/data/%BUILD_ID%/*  /.netlify/functions/next_all  200
 /page  /.netlify/functions/next_page  200
 /  /.netlify/functions/next_all  200
+/_next/*  /_next/:splat  200
 /*  /.netlify/functions/next_all  200"
 `;