[docs infra] speed up vercel build with ISR (#6773)

* [docs infra] speed up vercel build with ISR
* 60 -> 600

docs/next/pages/[...page].tsx

@@ -11,7 +11,7 @@ import Link from "../components/Link";
 import { MdxRemote } from "next-mdx-remote/types";
 import { NextSeo } from "next-seo";
 import SidebarNavigation, { getItems } from "components/mdx/SidebarNavigation";
-import { allPaths } from "util/useNavigation";
+import { latestAllPaths } from "util/useNavigation";
 import { promises as fs } from "fs";
 import generateToc from "mdast-util-toc";
 import hydrate from "next-mdx-remote/hydrate";
@@ -393,7 +393,7 @@ export const getStaticProps: GetStaticProps = async ({ params }) => {
           githubLink,
         },
       },
-      revalidate: 10, // In seconds
+      revalidate: 600, // In seconds; This enables Incremental Static Regeneration
     };
   } catch (err) {
     console.error(err);
@@ -405,7 +405,7 @@ export const getStaticProps: GetStaticProps = async ({ params }) => {
 
 export function getStaticPaths({}) {
   return {
-    paths: allPaths(),
+    paths: latestAllPaths(), // only generate pages of latest version at build time
     fallback: true,
   };
 }

docs/next/util/useNavigation.ts

@@ -1,5 +1,5 @@
 import masterNavigation from "../../content/_navigation.json";
-import { useVersion } from "./useVersion";
+import { useVersion, latestVersion } from "./useVersion";
 import versionedNavigation from "../.versioned_content/_versioned_navigation.json";
 
 export function flatten(yx: any) {
@@ -26,8 +26,8 @@ export const useNavigation = () => {
 };
 
 export const latestAllPaths = () => {
-  // Master
-  return flatten(masterNavigation)
+  // latest version
+  return flatten(versionedNavigation[latestVersion])
     .filter((n: { path: any }) => n.path)
     .map(({ path }) => path.split("/").splice(1))
     .map((page: string[]) => {

docs/next/util/useVersion.ts

@@ -7,7 +7,7 @@ const defaultVersion =
   process.env.NODE_ENV === "production"
     ? ALL_VERSIONS[ALL_VERSIONS.length - 1]
     : "master";
-const latestVersion = ALL_VERSIONS[ALL_VERSIONS.length - 1];
+export const latestVersion = ALL_VERSIONS[ALL_VERSIONS.length - 1];
 
 export function normalizeVersionPath(
   asPath: string,