refactor(v2): avoid synchronous/ blocking operation when possible (#1957)

* perf(v2): avoid synchronous/ blocking operation when possible

* save variable

packages/docusaurus-plugin-content-docs/src/__tests__/sidebars.test.ts

@@ -52,4 +52,10 @@ describe('loadSidebars', () => {
     const result = loadSidebars(null);
     expect(result).toEqual({});
   });
+
+  test('fake sidebars path', () => {
+    expect(() => {
+      loadSidebars('/fake/path');
+    }).toThrowError();
+  });
 });

packages/docusaurus-plugin-content-docs/src/sidebars.ts

@@ -5,7 +5,6 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import fs from 'fs';
 import importFresh from 'import-fresh';
 import {
   SidebarItemCategory,
@@ -105,7 +104,7 @@ function normalizeSidebar(sidebars: SidebarRaw): Sidebar {
 export default function loadSidebars(sidebarPath: string): Sidebar {
   // We don't want sidebars to be cached because of hotreloading.
   let allSidebars: SidebarRaw = {};
-  if (sidebarPath && fs.existsSync(sidebarPath)) {
+  if (sidebarPath) {
     allSidebars = importFresh(sidebarPath) as SidebarRaw;
   }
   return normalizeSidebar(allSidebars);

packages/docusaurus/src/client/serverEntry.js

@@ -14,17 +14,17 @@ import {getBundles} from 'react-loadable-ssr-addon';
 import Loadable from 'react-loadable';
 
 import path from 'path';
-import fs from 'fs';
+import fs from 'fs-extra';
 import routes from '@generated/routes';
 import preload from './preload';
 import App from './App';
 import ssrTemplate from './templates/ssr.html.template';
 
 // Renderer for static-site-generator-webpack-plugin (async rendering via promises)
-export default function render(locals) {
+export default async function render(locals) {
   const {routesLocation} = locals;
   const location = routesLocation[locals.path];
-  return preload(routes, location).then(() => {
+  await preload(routes, location);
   const modules = new Set();
   const context = {};
   const appHtml = ReactDOMServer.renderToString(
@@ -47,12 +47,12 @@ export default function render(locals) {
 
   const {outDir} = locals;
   const manifestPath = path.join(outDir, 'client-manifest.json');
-    const manifest = JSON.parse(fs.readFileSync(manifestPath, 'utf8'));
+  const manifest = JSON.parse(await fs.readFile(manifestPath, 'utf8'));
 
   // chunkName -> chunkAssets mapping.
   const chunkManifestPath = path.join(outDir, 'chunk-map.json');
   const chunkManifest = JSON.parse(
-      fs.readFileSync(chunkManifestPath, 'utf-8'),
+    await fs.readFile(chunkManifestPath, 'utf8'),
   );
   const chunkManifestScript =
     `<script type="text/javascript">` +
@@ -84,5 +84,4 @@ export default function render(locals) {
       rmWhitespace: true,
     },
   );
-  });
 }

packages/docusaurus/src/commands/build.ts

@@ -110,7 +110,9 @@ export async function build(
   // Remove server.bundle.js because it is useless
   if (serverConfig.output && serverConfig.output.filename) {
     const serverBundle = path.join(outDir, serverConfig.output.filename);
-    fs.existsSync(serverBundle) && fs.unlinkSync(serverBundle);
+    fs.pathExists(serverBundle).then(exist => {
+      exist && fs.unlink(serverBundle);
+    });
   }
 
   /* Plugin lifecycle - postBuild */

packages/docusaurus/src/webpack/plugins/ChunkManifestPlugin.js

@@ -26,7 +26,7 @@ class ChunkManifestPlugin {
     const {path: outputPath, publicPath} = compiler.options.output;
 
     // Build the chunk mapping
-    compiler.hooks.afterCompile.tap(pluginName, compilation => {
+    compiler.hooks.afterCompile.tapAsync(pluginName, (compilation, done) => {
       const assets = {};
       const assetsMap = {};
       // eslint-disable-next-line
@@ -50,8 +50,11 @@ class ChunkManifestPlugin {
       chunkManifest = assetsMap;
       if (!this.options.inlineManifest) {
         const finalPath = path.resolve(outputPath, this.options.filename);
-        fs.ensureDirSync(path.dirname(finalPath));
+        fs.ensureDir(path.dirname(finalPath), () => {
-        fs.writeFileSync(finalPath, JSON.stringify(chunkManifest, null, 2));
+          fs.writeFile(finalPath, JSON.stringify(chunkManifest, null, 2), done);
+        });
+      } else {
+        done();
       }
     });
 

packages/docusaurus/src/webpack/plugins/WaitPlugin.js

@@ -18,8 +18,7 @@ class WaitPlugin {
     // Before finishing the compilation step
     compiler.hooks.make.tapAsync('WaitPlugin', (compilation, callback) => {
       // To prevent 'waitFile' error on waiting non-existing directory
-      fs.ensureDirSync(path.dirname(this.filepath));
+      fs.ensureDir(path.dirname(this.filepath), () => {
-
         // Wait until file exist
         waitFile({
           resources: [this.filepath],
@@ -32,6 +31,7 @@ class WaitPlugin {
             console.warn(`WaitPlugin error: ${error}`);
           });
       });
+    });
   }
 }