chore: add comments

Author: ascorbic

demo/pages/getStaticProps/withRevalidate/[id].js

@@ -33,7 +33,7 @@ export async function getStaticProps({ params }) {
   const res = await fetch(`https://api.tvmaze.com/shows/${id}`)
   const data = await res.json()
   const time = new Date().toLocaleTimeString()
-  await new Promise((resolve) => setTimeout(resolve, 10000))
+  await new Promise((resolve) => setTimeout(resolve, 1000))
   return {
     props: {
       show: data,

src/helpers/config.js

@@ -78,8 +78,9 @@ exports.generateRedirects = async ({ netlifyConfig, basePath, i18n }) => {
   const staticRouteEntries = Object.entries(staticRoutes)
 
   staticRouteEntries.forEach(([route, { dataRoute, initialRevalidateSeconds }]) => {
-    // With revalidate we need to rewrite to SSR rather than ODB
+    // Only look for revalidate as we need to rewrite these to SSR rather than ODB
     if (initialRevalidateSeconds === false) {
+      // These can be ignored, as they're static files handled by the CDN
       return
     }
     if (i18n.defaultLocale && route.startsWith(`/${i18n.defaultLocale}/`)) {
@@ -104,30 +105,48 @@ exports.generateRedirects = async ({ netlifyConfig, basePath, i18n }) => {
 
   // This is only used in prod, so dev uses `next dev` directly
   netlifyConfig.redirects.push(
+    // Static files are in `static`
     { from: `${basePath}/_next/static/*`, to: `/static/:splat`, status: 200 },
+    // API routes always need to be served from the regular function
+    {
+      from: `${basePath}/api`,
+      to: HANDLER_FUNCTION_PATH,
+      status: 200,
+    },
+    {
+      from: `${basePath}/api/*`,
+      to: HANDLER_FUNCTION_PATH,
+      status: 200,
+    },
+    // Preview mode gets forced to the function, to bypess pre-rendered pages
     {
       from: `${basePath}/*`,
       to: HANDLER_FUNCTION_PATH,
       status: 200,
       conditions: { Cookie: ['__prerender_bypass', '__next_preview_data'] },
       force: true,
     },
+    // ISR redirects are handled by the regular function. Forced to avoid pre-rendered pages
     ...isrRedirects.map((redirect) => ({
       from: `${basePath}${redirect}`,
       to: HANDLER_FUNCTION_PATH,
       status: 200,
       force: true,
     })),
+    // These are pages with fallback set, which need an ODB
+    // Data redirects go first, to avoid conflict with splat redirects
     ...dataRedirects.map((redirect) => ({
       from: `${basePath}${redirect}`,
       to: ODB_FUNCTION_PATH,
       status: 200,
     })),
+    // ...then all the other fallback pages
     ...pageRedirects.map((redirect) => ({
       from: `${basePath}${redirect}`,
       to: ODB_FUNCTION_PATH,
       status: 200,
     })),
+    // Everything else is handled by the regular function
     { from: `${basePath}/*`, to: HANDLER_FUNCTION_PATH, status: 200 },
   )
   if (hasIsr) {

src/helpers/files.js

@@ -53,6 +53,7 @@ exports.moveStaticPages = async ({ netlifyConfig, target, i18n }) => {
 
   Object.entries(prerenderManifest.routes).forEach(([route, { initialRevalidateSeconds }]) => {
     if (initialRevalidateSeconds) {
+      // Find all files used by ISR routes
       const trimmedPath = route.slice(1)
       isrFiles.add(`${trimmedPath}.html`)
       isrFiles.add(`${trimmedPath}.json`)
@@ -83,6 +84,7 @@ exports.moveStaticPages = async ({ netlifyConfig, target, i18n }) => {
   const limit = pLimit(Math.max(2, cpus().length))
   const promises = pages.map(async (rawPath) => {
     const filePath = slash(rawPath)
+    // Don't move ISR files, as they're used for the first request
     if (isrFiles.has(filePath)) {
       return
     }

src/templates/getHandler.js

@@ -20,9 +20,11 @@ const makeHandler =
       require.resolve('./pages.js')
     } catch {}
 
+    // We don't want to write ISR files to disk in the lambda environment
+    conf.experimental.isrFlushToDisk = false
+
     // Set during the request as it needs the host header. Hoisted so we can define the function once
     let base
-    conf.experimental.isrFlushToDisk = false
 
     // Only do this if we have some static files moved to the CDN
     if (staticManifest.length !== 0) {
@@ -42,11 +44,11 @@ const makeHandler =
         if (file.startsWith(pageRoot)) {
           // We only want the part after `pages/`
           const filePath = file.slice(pageRoot.length + 1)
-          const cacheFile = path.join(cacheDir, filePath)
 
           // Is it in the CDN and not local?
           if (staticFiles.has(filePath) && !existsSync(file)) {
             // This name is safe to use, because it's one that was already created by Next
+            const cacheFile = path.join(cacheDir, filePath)
             // Have we already cached it? We ignore the cache if running locally to avoid staleness
             if ((!existsSync(cacheFile) || process.env.NETLIFY_DEV) && base) {
               await promises.mkdir(path.dirname(cacheFile), { recursive: true })