Allow middleware array merge by a key in item objects

lib/config-loader.js

@@ -1,6 +1,7 @@
 var fs = require('fs');
 var path = require('path');
 var debug = require('debug')('loopback:boot:config-loader');
+var assert = require('assert');
 
 var ConfigLoader = exports;
 
@@ -173,36 +174,59 @@ function mergeMiddlewareConfig(target, config, fileName) {
   }
 }
 
+function mergeNamedItems(arr1, arr2, key) {
+  assert(Array.isArray(arr1), 'invalid array: ' + arr1);
+  assert(Array.isArray(arr2), 'invalid array: ' + arr2);
+  key = key || 'name';
+  var result = [].concat(arr1);
+  for (var i = 0, n = arr2.length; i < n; i++) {
+    var item = arr2[i];
+    var found = false;
+    if (item[key]) {
+      for (var j = 0, k = result.length; j < k; j++) {
+        if (result[j][key] === item[key]) {
+          mergeObjects(result[j], item);
+          found = true;
+          break;
+        }
+      }
+    }
+    if (!found) {
+      result.push(item);
+    }
+  }
+  return result;
+}
+
 function mergePhaseConfig(target, config, phase) {
   var err;
-  for (var middleware in config) {
+  for (var mw in config) {
-    if (middleware in target) {
+    if (mw in target) {
-      var targetMiddleware = target[middleware];
+      var targetMiddleware = target[mw];
-      var configMiddleware = config[middleware];
+      var configMiddleware = config[mw];
       if (Array.isArray(targetMiddleware) && Array.isArray(configMiddleware)) {
         // Both are arrays, combine them
-        target[middleware] = targetMiddleware.concat(configMiddleware);
+        target[mw] = mergeNamedItems(targetMiddleware, configMiddleware);
       } else if (Array.isArray(targetMiddleware)) {
         if (typeof configMiddleware === 'object' &&
           Object.keys(configMiddleware).length) {
           // Config side is an non-empty object
-          targetMiddleware.push(configMiddleware);
+          target[mw] = mergeNamedItems(targetMiddleware, [configMiddleware]);
         }
       } else if (Array.isArray(configMiddleware)) {
         if (typeof targetMiddleware === 'object' &&
           Object.keys(targetMiddleware).length) {
           // Target side is an non-empty object
-          targetMiddleware = target[middleware] =
+          target[mw] = mergeNamedItems([targetMiddleware], configMiddleware);
-            [targetMiddleware].concat(configMiddleware);
         } else {
           // Target side is empty
-          target[middleware] = configMiddleware;
+          target[mw] = configMiddleware;
         }
       } else {
         err = mergeObjects(targetMiddleware, configMiddleware);
       }
     } else {
-      err = 'The middleware "' + middleware + '" in phase "' + phase + '"' +
+      err = 'The middleware "' + mw + '" in phase "' + phase + '"' +
         'is not defined in the main config.';
     }
     if (err) return err;

test/compiler.test.js

@@ -1850,6 +1850,59 @@ describe('compiler', function() {
         ]);
     });
 
+    it('merges config.params array to array by name', function() {
+      appdir.writeConfigFileSync('./middleware.json', {
+        routes: {
+          './middleware': [{
+            name: 'a',
+            params: {
+              key: 'initial value'
+            }
+          }]
+        }
+      });
+
+      appdir.writeConfigFileSync('./middleware.local.json', {
+        routes: {
+          './middleware': [{
+            name: 'a',
+            params: {
+              key: 'custom value'
+            }
+          }, {
+            params: {
+              key: '2nd value'
+            }
+          }]
+        }
+      });
+
+      var instructions = boot.compile(appdir.PATH);
+
+      expect(instructions.middleware.middleware)
+        .to.eql([
+          {
+            sourceFile: path.resolve(appdir.PATH, 'middleware'),
+            config: {
+              name: 'a',
+              phase: 'routes',
+              params: {
+                key: 'custom value'
+              }
+            }
+          },
+          {
+            sourceFile: path.resolve(appdir.PATH, 'middleware'),
+            config: {
+              phase: 'routes',
+              params: {
+                key: '2nd value'
+              }
+            }
+          }
+        ]);
+    });
+
     it('flattens sub-phases', function() {
       appdir.writeConfigFileSync('middleware.json', {
         'initial:after': {