diff --git a/packages/docusaurus/src/commands/start.ts b/packages/docusaurus/src/commands/start.ts
index 96c20efa1a9c..c05be5c9bcd1 100644
--- a/packages/docusaurus/src/commands/start.ts
+++ b/packages/docusaurus/src/commands/start.ts
@@ -10,7 +10,6 @@ import chalk = require('chalk');
 import chokidar from 'chokidar';
 import express from 'express';
 import HtmlWebpackPlugin from 'html-webpack-plugin';
-import _ from 'lodash';
 import path from 'path';
 import portfinder from 'portfinder';
 import openBrowser from 'react-dev-utils/openBrowser';
@@ -64,11 +63,12 @@ export async function start(
     return posixPath(filepath);
   };
 
-  const pluginPaths: string[] = _.compact(
-    _.flatten<string | undefined>(
-      plugins.map(plugin => plugin.getPathsToWatch && plugin.getPathsToWatch()),
-    ),
-  ).map(normalizeToSiteDir);
+  const pluginPaths: string[] = ([] as string[]).concat(
+    ...plugins
+      .map<any>(plugin => plugin.getPathsToWatch && plugin.getPathsToWatch())
+      .filter(Boolean)
+      .map(normalizeToSiteDir),
+  );
   const fsWatcher = chokidar.watch([...pluginPaths, CONFIG_FILE_NAME], {
     cwd: siteDir,
     ignoreInitial: true,
diff --git a/packages/docusaurus/src/server/client-modules/index.ts b/packages/docusaurus/src/server/client-modules/index.ts
index 2826802d5b8e..1c7dba2ca94b 100644
--- a/packages/docusaurus/src/server/client-modules/index.ts
+++ b/packages/docusaurus/src/server/client-modules/index.ts
@@ -5,19 +5,12 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import _ from 'lodash';
 import {Plugin} from '@docusaurus/types';
 
 export function loadClientModules(plugins: Plugin<any>[]): string[] {
-  return _.compact(
-    _.flatten<string | null>(
-      plugins.map(plugin => {
-        if (!plugin.getClientModules) {
-          return null;
-        }
-
-        return plugin.getClientModules();
-      }),
-    ),
+  return ([] as string[]).concat(
+    ...plugins
+      .map<any>(plugin => plugin.getClientModules && plugin.getClientModules())
+      .filter(Boolean),
   );
 }
diff --git a/packages/docusaurus/src/server/html-tags/index.ts b/packages/docusaurus/src/server/html-tags/index.ts
index 6c4b58760b77..03c3f72ea3ec 100644
--- a/packages/docusaurus/src/server/html-tags/index.ts
+++ b/packages/docusaurus/src/server/html-tags/index.ts
@@ -5,7 +5,6 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import _ from 'lodash';
 import {htmlTagObjectToString} from './htmlTags';
 import {
   Plugin,
@@ -19,7 +18,7 @@ function toString(val: string | HtmlTagObject): string {
 }
 
 export function createHtmlTagsString(tags: HtmlTags): string {
-  return _.isArray(tags) ? tags.map(toString).join('\n') : toString(tags);
+  return Array.isArray(tags) ? tags.map(toString).join('\n') : toString(tags);
 }
 
 export function loadHtmlTags(plugins: Plugin<any>[]): InjectedHtmlTags {
diff --git a/packages/docusaurus/src/server/index.ts b/packages/docusaurus/src/server/index.ts
index acb97cf58180..266737a3e691 100644
--- a/packages/docusaurus/src/server/index.ts
+++ b/packages/docusaurus/src/server/index.ts
@@ -6,7 +6,6 @@
  */
 
 import {generate} from '@docusaurus/utils';
-import _ from 'lodash';
 import path from 'path';
 import {
   BUILD_DIR_NAME,
@@ -85,8 +84,10 @@ export async function load(
 
   // Themes.
   const fallbackTheme = path.resolve(__dirname, '../client/theme-fallback');
-  const pluginThemes = _.compact(
-    plugins.map(plugin => plugin.getThemePath && plugin.getThemePath()),
+  const pluginThemes = ([] as string[]).concat(
+    ...plugins
+      .map<any>(plugin => plugin.getThemePath && plugin.getThemePath())
+      .filter(Boolean),
   );
   const userTheme = path.resolve(siteDir, THEME_PATH);
   const alias = loadThemeAlias([fallbackTheme, ...pluginThemes], [userTheme]);
diff --git a/packages/docusaurus/src/server/plugins/init.ts b/packages/docusaurus/src/server/plugins/init.ts
index 5e49831d68be..5898d2cdebf6 100644
--- a/packages/docusaurus/src/server/plugins/init.ts
+++ b/packages/docusaurus/src/server/plugins/init.ts
@@ -5,7 +5,6 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import _ from 'lodash';
 import importFresh from 'import-fresh';
 import {LoadContext, Plugin, PluginConfig} from '@docusaurus/types';
 
@@ -16,8 +15,8 @@ export function initPlugins({
   pluginConfigs: PluginConfig[];
   context: LoadContext;
 }): Plugin<any>[] {
-  const plugins: Plugin<any>[] = _.compact(
-    pluginConfigs.map(pluginItem => {
+  const plugins: Plugin<any>[] = pluginConfigs
+    .map(pluginItem => {
       let pluginModuleImport;
       let pluginOptions = {};
 
@@ -40,8 +39,8 @@ export function initPlugins({
       // module identifier - npm package or locally-resolved path.
       const pluginModule: any = importFresh(pluginModuleImport);
       return (pluginModule.default || pluginModule)(context, pluginOptions);
-    }),
-  );
+    })
+    .filter(Boolean);
 
   return plugins;
 }
diff --git a/packages/docusaurus/src/server/presets/index.ts b/packages/docusaurus/src/server/presets/index.ts
index 75f1e3f5f009..cd09f1fede34 100644
--- a/packages/docusaurus/src/server/presets/index.ts
+++ b/packages/docusaurus/src/server/presets/index.ts
@@ -6,7 +6,6 @@
  */
 
 import importFresh from 'import-fresh';
-import _ from 'lodash';
 import {
   LoadContext,
   PluginConfig,
@@ -47,7 +46,7 @@ export function loadPresets(
   });
 
   return {
-    plugins: _.compact(_.flatten<PluginConfig>(unflatPlugins)),
-    themes: _.compact(_.flatten<PluginConfig>(unflatThemes)),
+    plugins: ([] as PluginConfig[]).concat(...unflatPlugins).filter(Boolean),
+    themes: ([] as PluginConfig[]).concat(...unflatThemes).filter(Boolean),
   };
 }
diff --git a/packages/docusaurus/src/server/routes.ts b/packages/docusaurus/src/server/routes.ts
index 67e00e579789..1e3586c6d1fb 100644
--- a/packages/docusaurus/src/server/routes.ts
+++ b/packages/docusaurus/src/server/routes.ts
@@ -85,7 +85,7 @@ export async function loadRoutes(
         return null;
       }
 
-      if (_.isArray(value)) {
+      if (Array.isArray(value)) {
         return value.map((val, index) =>
           genRouteChunkNames(val, `${index}`, name),
         );
@@ -113,7 +113,8 @@ export async function loadRoutes(
       return newValue;
     }
 
-    routesChunkNames[routePath] = _.assign(
+    routesChunkNames[routePath] = Object.assign(
+      {},
       routesChunkNames[routePath],
       genRouteChunkNames({component}, 'component', component),
       genRouteChunkNames(modules, 'module', routePath),