Replace lodash with native JS equivalents (#522)

Frank3K · web-flow · commit d2154f1f7014 · 2026-03-19T10:46:25.000-07:00
* Replace lodash with native JS equivalents

Removes lodash (and @types/lodash) as a dependency. All usages are
replaced with native ES2020 equivalents: optional chaining, Array
methods, Object.entries/spread, and typeof checks. A shared
isPlainObject helper is extracted to src/utils/objectutils.js.

* Convert objectutils.js to TypeScript

Replaces the CommonJS module with a typed ES module export.
Adds a `val is Record&lt;string, unknown&gt;` type predicate so callers
get proper type narrowing when using `isPlainObject`.

* Add license header to objectutils.ts
diff --git a/package-lock.json b/package-lock.json
diff --git a/package.json b/package.json
@@ -59,7 +59,6 @@
     "glob-slasher": "^1.0.1",
     "is-url": "^1.2.2",
     "join-path": "^1.1.1",
-    "lodash": "^4.17.19",
     "mime-types": "^2.1.35",
     "minimatch": "^6.1.6",
     "morgan": "^1.8.2",
@@ -77,7 +76,6 @@
     "@types/chai": "^4.3.3",
     "@types/chai-as-promised": "^7.1.5",
     "@types/connect": "^3.4.35",
-    "@types/lodash": "^4.14.186",
     "@types/mime-types": "^2.1.1",
     "@types/mocha": "^10.0.0",
     "@types/node": "^24.3.1",
diff --git a/src/activator.js b/src/activator.js
@@ -20,15 +20,14 @@
  */
 
 const middleware = require("./middleware");
-const _ = require("lodash");
 const promiseback = require("./utils/promiseback");
 
 const Activator = function (spec, provider) {
   this.spec = spec;
   this.provider = provider;
   this.stack = this.buildStack();
 
-  if (_.isFunction(spec.config)) {
+  if (typeof spec.config === "function") {
     this.awaitConfig = spec.config;
   } else {
     this.awaitConfig = function () {
@@ -41,16 +40,16 @@ Activator.prototype.buildStack = function () {
   const self = this;
 
   const stack = this.spec.stack.slice(0);
-  _.forEach(this.spec.before, (wares, name) => {
+  Object.entries(this.spec.before ?? {}).forEach(([name, wares]) => {
     stack.splice(...[stack.indexOf(name), 0].concat(wares));
   });
 
-  _.forEach(this.spec.after, (wares, name) => {
+  Object.entries(this.spec.after ?? {}).forEach(([name, wares]) => {
     stack.splice(...[stack.indexOf(name) + 1, 0].concat(wares));
   });
 
   return stack.map((ware) => {
-    return _.isFunction(ware) ? ware : middleware[ware](self.spec);
+    return typeof ware === "function" ? ware : middleware[ware](self.spec);
   });
 };
 
diff --git a/src/loaders/config-file.js b/src/loaders/config-file.js
@@ -21,14 +21,14 @@
 
 const fs = require("fs");
 
-const _ = require("lodash");
 const join = require("join-path");
 const path = require("path");
+const { isPlainObject } = require("../utils/objectutils");
 
 const CONFIG_FILE = ["superstatic.json", "firebase.json"];
 
 module.exports = function (filename) {
-  if (_.isFunction(filename)) {
+  if (typeof filename === "function") {
     return filename;
   }
 
@@ -41,26 +41,26 @@ module.exports = function (filename) {
   try {
     configObject = JSON.parse(filename);
   } catch {
-    if (_.isPlainObject(filename)) {
+    if (isPlainObject(filename)) {
       configObject = filename;
       filename = CONFIG_FILE;
     }
   }
 
-  if (_.isArray(filename)) {
-    filename = _.find(filename, (name) => {
+  if (Array.isArray(filename)) {
+    filename = filename.find((name) => {
       return fs.existsSync(join(process.cwd(), name));
     });
   }
 
   // Set back to default config file if stringified object is
   // given as config. With this, we override values in the config file
-  if (_.isPlainObject(filename)) {
+  if (isPlainObject(filename)) {
     filename = CONFIG_FILE;
   }
 
   // A file name or array of file names
-  if (_.isString(filename) && _.endsWith(filename, "json")) {
+  if (typeof filename === "string" && filename.endsWith("json")) {
     try {
       config = JSON.parse(fs.readFileSync(path.resolve(filename)));
       config = config.hosting ?? config;
@@ -71,5 +71,5 @@ module.exports = function (filename) {
 
   // Passing an object as the config value merges
   // the config data
-  return _.assign(config, configObject);
+  return { ...config, ...configObject };
 };
diff --git a/src/middleware/files.js b/src/middleware/files.js
@@ -19,7 +19,6 @@
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
 
-const _ = require("lodash");
 const { i18nContentOptions } = require("../utils/i18n");
 const pathutils = require("../utils/pathutils");
 const url = require("url");
@@ -42,17 +41,17 @@ module.exports = function () {
     const pathname = pathutils.normalizeMultiSlashes(parsedUrl.pathname);
     const search = parsedUrl.search ?? "";
 
-    const cleanUrlRules = !!_.get(req, "superstatic.cleanUrls");
+    const cleanUrlRules = !!req?.superstatic?.cleanUrls;
 
     // Exact file always wins.
     return providerResult(req, res, pathname)
       .then((result) => {
         if (result) {
           // If we are using cleanURLs, we'll trim off any `.html` (or `/index.html`), if it exists.
           if (cleanUrlRules) {
-            if (_.endsWith(pathname, ".html")) {
+            if (pathname.endsWith(".html")) {
               let redirPath = pathutils.removeTrailingString(pathname, ".html");
-              if (_.endsWith(redirPath, "/index")) {
+              if (redirPath.endsWith("/index")) {
                 redirPath = pathutils.removeTrailingString(redirPath, "/index");
               }
               if (trailingSlashBehavior === true) {
@@ -154,7 +153,7 @@ module.exports = function () {
                       });
                     }
                     // If we've gotten this far and still have `/index.html` on the end, we want to remove it from the URL.
-                    if (_.endsWith(appendedPath, "/index.html")) {
+                    if (appendedPath.endsWith("/index.html")) {
                       return res.superstatic.handle({
                         redirect: normalizeRedirectPath(
                           pathutils.removeTrailingString(
diff --git a/src/middleware/headers.js b/src/middleware/headers.js
@@ -19,17 +19,16 @@
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
 
-const _ = require("lodash");
 const slasher = require("glob-slasher");
 const urlParser = require("url");
 const onHeaders = require("on-headers");
 const patterns = require("../utils/patterns");
 
 const normalizedConfigHeaders = function (spec, config) {
   const out = config ?? [];
-  if (_.isArray(config)) {
+  if (Array.isArray(config)) {
     const _isAllowed = function (headerToSet) {
-      return _.includes(spec.allowedHeaders, headerToSet.key.toLowerCase());
+      return spec.allowedHeaders.includes(headerToSet.key.toLowerCase());
     };
 
     for (const c of config) {
@@ -61,7 +60,7 @@ const matcher = function (configHeaders) {
 
 module.exports = function (spec) {
   return function (req, res, next) {
-    const config = _.get(req, "superstatic.headers");
+    const config = req?.superstatic?.headers;
     if (!config) {
       return next();
     }
@@ -71,7 +70,7 @@ module.exports = function (spec) {
     const matches = headers(slasher(pathname));
 
     onHeaders(res, () => {
-      _.forEach(matches, (header) => {
+      matches.forEach((header) => {
         res.setHeader(header.key, header.value);
       });
     });
diff --git a/src/middleware/index.js b/src/middleware/index.js
@@ -19,8 +19,6 @@
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
 
-const _ = require("lodash");
-
 [
   "protect",
   "redirects",
@@ -31,7 +29,7 @@ const _ = require("lodash");
   "missing",
 ].forEach((name) => {
   exports[name] = function (spec, config) {
-    const mware = require("./" + _.kebabCase(name))(spec, config);
+    const mware = require("./" + name)(spec, config);
     mware._name = name;
     return mware;
   };
diff --git a/src/middleware/redirects.js b/src/middleware/redirects.js
@@ -20,7 +20,6 @@
  */
 
 const isUrl = require("is-url");
-const _ = require("lodash");
 
 const patterns = require("../utils/patterns");
 const pathToRegexp = require("path-to-regexp");
@@ -117,13 +116,13 @@ Redirect.prototype.test = function (url) {
 
 module.exports = function () {
   return function (req, res, next) {
-    const config = _.get(req, "superstatic.redirects");
+    const config = req?.superstatic?.redirects;
     if (!config) {
       return next();
     }
 
     const redirects = [];
-    if (_.isArray(config)) {
+    if (Array.isArray(config)) {
       config.forEach((redir) => {
         const glob = redir.glob ?? redir.source;
         redirects.push(
diff --git a/src/responder.js b/src/responder.js
@@ -19,8 +19,8 @@
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
 
-const _ = require("lodash");
 const mime = require("mime-types");
+const { isPlainObject } = require("./utils/objectutils");
 const path = require("path");
 const onFinished = require("on-finished");
 const destroy = require("destroy");
@@ -72,11 +72,11 @@ Responder.prototype.handle = function (item, next) {
 };
 
 Responder.prototype._handle = function (item) {
-  if (_.isArray(item)) {
+  if (Array.isArray(item)) {
     return this.handleStack(item);
-  } else if (_.isString(item)) {
+  } else if (typeof item === "string") {
     return this.handleFile({ file: item });
-  } else if (_.isPlainObject(item)) {
+  } else if (isPlainObject(item)) {
     if (item.file) {
       return this.handleFile(item);
     } else if (item.redirect) {
@@ -86,7 +86,7 @@ Responder.prototype._handle = function (item) {
     } else if (item.data) {
       return this.handleData(item);
     }
-  } else if (_.isFunction(item)) {
+  } else if (typeof item === "function") {
     return this.handleMiddleware(item);
   }
 
diff --git a/src/superstatic.js b/src/superstatic.js
@@ -19,7 +19,6 @@
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */
 
-const _ = require("lodash");
 const makerouter = require("router");
 
 const fsProvider = require("./providers/fs");
@@ -58,18 +57,11 @@ const superstatic = function (spec = {}) {
   // Set up provider
   const provider = spec.provider
     ? promiseback(spec.provider, 2)
-    : fsProvider(
-        _.extend(
-          {
-            cwd: cwd, // default current working directory
-          },
-          config,
-        ),
-      );
+    : fsProvider({ cwd, ...config });
 
   // Select compression middleware
   let compressor;
-  if (_.isFunction(spec.compression)) {
+  if (typeof spec.compression === "function") {
     compressor = spec.compression;
   } else if (spec.compression ?? spec.gzip) {
     compressor = defaultCompressor;
diff --git a/src/utils/objectutils.ts b/src/utils/objectutils.ts
@@ -0,0 +1,35 @@
+/**
+ * Copyright (c) 2026 Google LLC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+/**
+ * Returns true for plain objects (`{}` or `Object.create(null)`).
+ * @param val value to check
+ * @returns value indicating whether the value is a plain object
+ */
+export function isPlainObject(val: unknown): val is Record<string, unknown> {
+  return (
+    val !== null &&
+    typeof val === "object" &&
+    !Array.isArray(val) &&
+    (Object.getPrototypeOf(val) === Object.prototype ||
+      Object.getPrototypeOf(val) === null)
+  );
+}
diff --git a/test/unit/responder.spec.js b/test/unit/responder.spec.js
