Improve performance of plugins listing

packages/gitbook/src/plugins/findInstalled.js

@@ -1,5 +1,4 @@
-const readInstalled = require('read-installed');
-const Immutable = require('immutable');
+const { OrderedMap } = require('immutable');
 const path = require('path');
 
 const Promise = require('../utils/promise');
@@ -16,75 +15,61 @@ function validateId(name) {
     return name && name.indexOf(PREFIX) === 0;
 }
 
+/**
+ * Read details about a node module.
+ * @param {String} modulePath
+ * @param {Number} depth
+ * @param {String} parent
+ * @return {Plugin} plugin
+ */
+function readModule(modulePath, depth, parent) {
+    const pkg = require(path.join(modulePath, 'package.json'));
+    const pluginName = pkg.name.slice(PREFIX.length);
+
+    return new Plugin({
+        name: pluginName,
+        version: pkg.version,
+        path: modulePath,
+        depth,
+        parent
+    });
+}
 
 /**
  * List all packages installed inside a folder
  *
  * @param {String} folder
+ * @param {Number} depth
+ * @param {String} parent
  * @return {OrderedMap<String:Plugin>}
  */
-function findInstalled(folder) {
-    const options = {
-        dev: false,
-        log() {},
-        depth: 4
-    };
-    let results = Immutable.OrderedMap();
-
-    function onPackage(pkg, parent) {
-        if (!pkg.name) return;
-
-        const name = pkg.name;
-        const version = pkg.version;
-        const pkgPath = pkg.realPath;
-        const depth = pkg.depth;
-        const dependencies = pkg.dependencies;
-
-        const pluginName = name.slice(PREFIX.length);
-
-        if (!validateId(name)) {
-            if (parent) return;
-        } else {
-            results = results.set(pluginName, new Plugin({
-                name: pluginName,
-                version,
-                path: pkgPath,
-                depth,
-                parent
-            }));
-        }
-
-        Immutable.Map(dependencies).forEach(function(dep) {
-            onPackage(dep, pluginName);
-        });
-    }
-
+function findInstalled(folder, depth = 0, parent = null) {
     // Search for gitbook-plugins in node_modules folder
     const node_modules = path.join(folder, 'node_modules');
 
     // List all folders in node_modules
     return fs.readdir(node_modules)
-    .fail(function() {
+    .fail(() => {
         return Promise([]);
     })
-    .then(function(modules) {
-        return Promise.serie(modules, function(module) {
+    .then((modules) => {
+        return Promise.reduce(modules, (results, moduleName) => {
             // Not a gitbook-plugin
-            if (!validateId(module)) {
-                return Promise();
+            if (!validateId(moduleName)) {
+                return results;
             }
 
             // Read gitbook-plugin package details
-            const module_folder = path.join(node_modules, module);
-            return Promise.nfcall(readInstalled, module_folder, options)
-            .then(function(data) {
-                onPackage(data);
+            const moduleFolder = path.join(node_modules, moduleName);
+            const plugin = readModule(moduleFolder, depth, parent);
+
+            results = results.set(plugin.getName(), plugin);
+
+            return findInstalled(moduleFolder, depth + 1, plugin.getName())
+            .then((innerModules) => {
+                return results.merge(innerModules);
             });
-        });
-    })
-    .then(function() {
-        // Return installed plugins
-        return results;
+        }, OrderedMap());
     });
 }