Merge pull request #3 from strongloop/feature/fix-requires-of-nested-modules

Fix loading of loopback dependencies.

index.js

@@ -3,8 +3,8 @@
  */
 var path = require('path');
 var loopback = require('loopback');
-var swagger = require('loopback/node_modules/strong-remoting/ext/swagger');
+var swagger = requireLoopbackDependency('strong-remoting/ext/swagger');
-var express = require('loopback/node_modules/express');
+var express = requireLoopbackDependency('express');
 var STATIC_ROOT = path.join(__dirname, 'public');
 
 module.exports = explorer;
@@ -30,3 +30,24 @@ function explorer(loopbackApplication, options) {
   app.use(loopback.static(STATIC_ROOT));
   return app;
 }
+
+function requireLoopbackDependency(module) {
+  try {
+    return require('loopback/node_modules/' + module);
+  } catch (err) {
+    if (err.code !== 'MODULE_NOT_FOUND') throw err;
+    try {
+      // Dependencies may be installed outside the loopback module,
+      // e.g. as peer dependencies. Try to load the dependency from there.
+      return require(module);
+    } catch (errPeer) {
+      if (errPeer.code !== 'MODULE_NOT_FOUND') throw errPeer;
+      // Rethrow the initial error to make it clear that we were trying
+      // to load a module that should have been installed inside
+      // "loopback/node_modules". This should minimise end-user's confusion.
+      // However, such situation should never happen as `require('loopback')`
+      // would have failed before this function was even called.
+      throw err;
+    }
+  }
+}