Add routing support for catch-all routes

Create an adaptation of serverless-next.js' expressifyDynamicRoute
function: getNetlifyRoute. Our getNetlifyRoute function differs from
the expressifyDynamicRoute in that it converts catch-all routes from
[...params] to /:* rather than to /:params*. The latter does not work
with Netlify routing, but our version does.

Author: FinnWoelm

lib/collectNextjsPages.js

@@ -8,6 +8,7 @@
 // - Structure is an array of objects (was an object of objects)
 
 const readPagesManifest       = require('./readPagesManifest')
+const getNetlifyRoute         = require('./getNetlifyRoute')
 const isDynamicRoute          = require("./serverless-next.js/isDynamicRoute")
 const expressifyDynamicRoute  = require("./serverless-next.js/expressifyDynamicRoute")
 const pathToRegexStr          = require("./serverless-next.js/pathToRegexStr")
@@ -33,10 +34,14 @@ function collectNextjsPages() {
 
     // Route to the page (/about)
     // If the page is dynamic, use url segments: /posts/[id] --> /posts/:id
-    page.route = page.isDynamic ? expressifyDynamicRoute(route) : route
+    page.route = page.isDynamic ? getNetlifyRoute(route) :route
 
     // Regex for matching the page (/^\/about$/)
-    page.regex = pathToRegexStr(page.route)
+    // NOTE: This route is different than the Netlify route set above!
+    //       They are very similar, but not the same. See getNetlifyRoute.js for
+    //       more information.
+    const _route = page.isDynamic ? expressifyDynamicRoute(route) : route
+    page.regex = pathToRegexStr(_route)
 
     return page
   })

lib/getNetlifyRoute.js

@@ -0,0 +1,15 @@
+// Adapted from serverless-next.js (v1.9.10)
+// https://github.com/danielcondemarin/serverless-next.js/blob/master/packages/serverless-nextjs-component/lib/expressifyDynamicRoute.js
+// The original turns catch-all routes from /[...params] into /:params*
+// This adaptation turns catch-all routes from /[...params] into /:*
+// This is necessary for it to work with Netlify routing.
+
+// converts a nextjs dynamic route /[param]/ -> /:param
+// also handles catch all routes /[...param]/ -> /:*
+module.exports = dynamicRoute => {
+  // replace any catch all group first
+  let expressified = dynamicRoute.replace(/\[\.\.\.(.*)]$/, "*");
+
+  // now replace other dynamic route groups
+  return expressified.replace(/\[(.*?)]/g, ":$1");
+};