From 2e33758bef3ce2adff379879f39a45965ac6ad63 Mon Sep 17 00:00:00 2001
From: Frank Li <frankli1@fb.com>
Date: Fri, 11 Aug 2017 11:39:04 -0700
Subject: [PATCH] Clean up cache removal function

---
 lib/server/server.js | 70 +++++++++++++++-----------------------------
 1 file changed, 23 insertions(+), 47 deletions(-)

diff --git a/lib/server/server.js b/lib/server/server.js
index 88a48a0385..dec74641bd 100644
--- a/lib/server/server.js
+++ b/lib/server/server.js
@@ -29,17 +29,19 @@ function execute(port) {
 
   let siteConfig = require(CWD + "/siteConfig.js");
 
-  /**
-   * Removes a module from the cache
-   */
-  function purgeCache(moduleName) {
-    // Traverse the cache looking for the files
-    // loaded by the specified module name
-    searchCache(moduleName, function(mod) {
-      delete require.cache[mod.id];
-    });
+  // remove a module and child modules from require cache, so server does not have
+  // to be restarted
+  function removeFromCache(moduleName) {
+    let mod = require.resolve(moduleName);
+    if (mod && (mod = require.cache[mod])) {
+      (function traverse(mod) {
+        mod.children.forEach(child => {
+          traverse(child);
+        });
+        delete require.cache[mod.id];
+      })(mod);
+    }
 
-    // Remove cached paths to the module.
     Object.keys(module.constructor._pathCache).forEach(function(cacheKey) {
       if (cacheKey.indexOf(moduleName) > 0) {
         delete module.constructor._pathCache[cacheKey];
@@ -47,42 +49,16 @@ function execute(port) {
     });
   }
 
-  /**
-   * Traverses the cache to search for all the cached
-   * files of the specified module name
-   */
-  function searchCache(moduleName, callback) {
-    // Resolve the module identified by the specified name
-    let mod = require.resolve(moduleName);
-
-    // Check if the module has been resolved and found within
-    // the cache
-    if (mod && (mod = require.cache[mod]) !== undefined) {
-      // Recursively go over the results
-      (function traverse(mod) {
-        // Go over each of the module's children and
-        // traverse them
-        mod.children.forEach(function(child) {
-          traverse(child);
-        });
-
-        // Call the specified callback providing the
-        // found cached module
-        callback(mod);
-      })(mod);
-    }
-  }
-
   /****************************************************************************/
 
   let readMetadata;
   let Metadata;
 
   function reloadMetadata() {
-    purgeCache("./readMetadata.js");
+    removeFromCache("./readMetadata.js");
     readMetadata = require("./readMetadata.js");
     readMetadata.generateDocsMetadata();
-    purgeCache("../core/metadata.js");
+    removeFromCache("../core/metadata.js");
     Metadata = require("../core/metadata.js");
   }
 
@@ -127,7 +103,7 @@ function execute(port) {
 
   /* handle all requests for document pages */
   const app = express().get(/docs\/.*html$/, (req, res, next) => {
-    purgeCache(CWD + "/siteConfig.js");
+    removeFromCache(CWD + "/siteConfig.js");
     siteConfig = require(CWD + "/siteConfig.js");
 
     let url = req.path.toString().replace(siteConfig.baseUrl, "");
@@ -222,7 +198,7 @@ function execute(port) {
       "](" + siteConfig.baseUrl + "docs/assets/"
     );
 
-    purgeCache("../core/DocsLayout.js");
+    removeFromCache("../core/DocsLayout.js");
     const DocsLayout = require("../core/DocsLayout.js");
     const docComp = (
       <DocsLayout metadata={metadata} language={language} config={siteConfig}>
@@ -235,17 +211,17 @@ function execute(port) {
 
   /* handle all requests for blog pages and posts */
   app.get(/blog\/.*html$/, (req, res) => {
-    purgeCache(CWD + "/siteConfig.js");
+    removeFromCache(CWD + "/siteConfig.js");
     siteConfig = require(CWD + "/siteConfig.js");
     if (fs.existsSync(__dirname + "/../core/MetadataBlog.js")) {
-      purgeCache("../core/MetadataBlog.js");
+      removeFromCache("../core/MetadataBlog.js");
       fs.removeSync(__dirname + "/../core/MetadataBlog.js");
     }
     readMetadata.generateBlogMetadata();
     const MetadataBlog = require("../core/MetadataBlog.js");
 
     /* generate all of the blog pages */
-    purgeCache("../core/BlogPageLayout.js");
+    removeFromCache("../core/BlogPageLayout.js");
     const BlogPageLayout = require("../core/BlogPageLayout.js");
     const blogPages = {};
     /* make blog pages with 10 posts per page */
@@ -304,7 +280,7 @@ function execute(port) {
       metadata.id = metadata.title;
 
       let language = "en";
-      purgeCache("../core/BlogPostLayout.js");
+      removeFromCache("../core/BlogPostLayout.js");
       const BlogPostLayout = require("../core/BlogPostLayout.js");
 
       const blogPostComp = (
@@ -322,7 +298,7 @@ function execute(port) {
 
   /* handle all other main pages */
   app.get("*.html", (req, res, next) => {
-    purgeCache(CWD + "/siteConfig.js");
+    removeFromCache(CWD + "/siteConfig.js");
     siteConfig = require(CWD + "/siteConfig.js");
 
     /* look for user provided html file first */
@@ -387,9 +363,9 @@ function execute(port) {
       fs.copySync(userFile, tempFile);
 
       /* render into a string */
-      purgeCache(tempFile);
+      removeFromCache(tempFile);
       const ReactComp = require(tempFile);
-      purgeCache("../core/Site.js");
+      removeFromCache("../core/Site.js");
       const Site = require("../core/Site.js");
       translate.setLanguage(language);
       const str = renderToStaticMarkup(