chore: log warning about isr (#565)

Author: lindsaylevine

src/lib/pages/getStaticPropsWithRevalidate/pages.js

@@ -1,3 +1,5 @@
+const { yellowBright } = require('chalk')
+
 const asyncForEach = require('../../helpers/asyncForEach')
 const getPrerenderManifest = require('../../helpers/getPrerenderManifest')
 const isRouteWithFallback = require('../../helpers/isRouteWithFallback')
@@ -9,10 +11,14 @@ const getPages = async () => {
   // Collect pages
   const pages = []
 
+  let usesRevalidateAtLeastOnce = false
+
   await asyncForEach(Object.entries(routes), async ([route, { dataRoute, srcRoute, initialRevalidateSeconds }]) => {
     // Skip pages without revalidate, these are handled by getStaticProps/pages
     if (!initialRevalidateSeconds) return
 
+    usesRevalidateAtLeastOnce = true
+
     // Skip pages with fallback, these are handled by
     // getStaticPropsWithFallback/pages
     if (await isRouteWithFallback(srcRoute)) return
@@ -24,6 +30,15 @@ const getPages = async () => {
       dataRoute,
     })
   })
+
+  if (usesRevalidateAtLeastOnce) {
+    console.log(
+      yellowBright(
+        `Warning: It looks like you're using the 'revalidate' flag in one of your Next.js pages.  Please read our docs about ISR on Netlify: https://ntl.fyi/next-isr-info`,
+      ),
+    )
+  }
+
   return pages
 }