config-loader: deeply merge Array and Object vals

lib/config-loader.js

@@ -129,11 +129,29 @@ function mergeAppConfig(target, config, fileName) {
 function applyCustomConfig(target, config) {
   for (var key in config) {
     var value = config[key];
-    if (typeof value === 'object') {
+    if (target[key]) {
-      return 'override for the option `' + key + '` is not a value type.';
+      if (Array.isArray(target[key]) && Array.isArray(value)) {
+        if (target[key].length == value.length) {
+          for (var valueIdx in value) {
+            if (typeof value[valueIdx] === 'object') {
+              applyCustomConfig(target[key][valueIdx], value[valueIdx]);
+            } else {
+              target[key][valueIdx] = value[valueIdx];
             }
+          }
+        } else {
+          return 'override for the option `' + key +
+            '` is an array and lengths mismatch.';
+        }
+      } else if (typeof target[key] === 'object' && typeof value === 'object') {
+        applyCustomConfig(target[key], value);
+      } else {
         target[key] = value;
       }
+    } else {
+      target[key] = value;
+    }
+  }
   return null; // no error
 }
 

test/compiler.test.js

@@ -125,24 +125,82 @@ describe('compiler', function() {
       expect(db).to.have.property('fromJs', true);
     });
 
-    it('refuses to merge Object properties', function() {
+    it('merges Object properties', function() {
+      var nestedValue = { key: 'value' };
       appdir.createConfigFilesSync();
       appdir.writeConfigFileSync('datasources.local.json', {
-        db: { nested: { key: 'value' } }
+        db: { nested: nestedValue }
+      });
+
+      var instructions = boot.compile(appdir.PATH);
+
+      var db = instructions.dataSources.db;
+      expect(db).to.have.property('nested');
+      expect(db.nested).to.eql(nestedValue);
+    });
+
+    it('merges nested Object properties', function() {
+      var nestedValue = 'http://api.test.com';
+      appdir.createConfigFilesSync();
+      appdir.writeConfigFileSync('datasources.local.json', {
+        rest: {
+          operations: [
+            {
+              template: {
+                url: nestedValue
+              }
+            }
+          ]
+        }
+      });
+
+      var instructions = boot.compile(appdir.PATH);
+
+      var rest = instructions.dataSources.rest;
+      expect(rest).to.have.property('operations');
+      expect(rest.operations[0]).to.have.property('template');
+      expect(rest.operations[0].template).to.have.property('url');
+      expect(rest.operations[0].template.method).to.eql('POST');
+      expect(rest.operations[0].template.url).to.eql(nestedValue);
+    });
+
+    it('merges Array properties', function() {
+      var nestedValue = ['value'];
+      appdir.createConfigFilesSync();
+      appdir.writeConfigFileSync('datasources.local.json', {
+        db: { nested: nestedValue }
+      });
+
+      var instructions = boot.compile(appdir.PATH);
+
+      var db = instructions.dataSources.db;
+      expect(db).to.have.property('nested');
+      expect(db.nested).to.eql(nestedValue);
+    });
+
+    it('errors on mismatched arrays', function() {
+      var nestedValue = 'http://api.test.com';
+      appdir.createConfigFilesSync();
+      appdir.writeConfigFileSync('datasources.local.json', {
+        rest: {
+          operations: [
+            {
+              template: {
+                url: nestedValue
+              }
+            },
+            {
+              template: {
+                method: 'GET',
+                url: nestedValue
+              }
+            }
+          ]
+        }
       });
 
       expect(function() { boot.compile(appdir.PATH); })
-        .to.throw(/`nested` is not a value type/);
+        .to.throw(/an array and lengths mismatch/);
-    });
-
-    it('refuses to merge Array properties', function() {
-      appdir.createConfigFilesSync();
-      appdir.writeConfigFileSync('datasources.local.json', {
-        db: { nested: ['value'] }
-      });
-
-      expect(function() { boot.compile(appdir.PATH); })
-        .to.throw(/`nested` is not a value type/);
     });
 
     it('merges app configs from multiple files', function() {

test/helpers/appdir.js

@@ -28,6 +28,16 @@ appdir.createConfigFilesSync = function(appConfig, dataSources, models) {
     db: {
       connector: 'memory',
       defaultForType: 'db'
+    },
+    rest: {
+      connector: 'rest',
+      operations: [
+        {
+          template: {
+            method: 'POST'
+          }
+        }
+      ]
     }
   }, dataSources);
   appdir.writeConfigFileSync ('datasources.json', dataSources);