fix _convertCase issues

closes #80

Author: danivek

Diff for: lib/JSONAPISerializer.js

@@ -764,38 +764,51 @@ module.exports = class JSONAPISerializer {
    * @returns {object} Object with it's keys converted as per the convertCaseOptions
    */
   _convertCase(data, convertCaseOptions) {
-    let converted;
-    if (typeof data === 'object') {
-      converted = transform(
-        data,
-        (result, value, key) => {
-          if (value && typeof value === 'object') {
-            result[this._convertCase(key, convertCaseOptions)] = this._convertCase(
-              value,
-              convertCaseOptions
-            );
-          } else {
-            result[this._convertCase(key, convertCaseOptions)] = value;
-          }
-          return result;
-        },
-        {}
-      );
-    } else {
-      switch (convertCaseOptions) {
-        case 'snake_case':
-          converted = toSnakeCase(data);
-          break;
-        case 'kebab-case':
-          converted = toKebabCase(data);
-          break;
-        case 'camelCase':
-          converted = toCamelCase(data);
-          break;
-        default: // Do nothing
+    if (data !== undefined && data !== null) {
+      if (Array.isArray(data)) {
+        return data.map(item => this._convertCase(item, convertCaseOptions));
+      }
+
+      if (typeof data === 'object') {
+        return transform(
+          data,
+          (result, value, key) => {
+            let converted;
+            if (value && Array.isArray(value)) {
+              converted = value.map(item => this._convertCase(item, convertCaseOptions));
+            } else if (value && typeof value === 'object') {
+              converted = this._convertCase(value, convertCaseOptions);
+            } else {
+              converted = value;
+            }
+
+            result[this._convertCase(key, convertCaseOptions)] = converted;
+            return result;
+          },
+          {}
+        );
+      }
+
+      if (typeof data === 'string') {
+        let converted;
+
+        switch (convertCaseOptions) {
+          case 'snake_case':
+            converted = toSnakeCase(data);
+            break;
+          case 'kebab-case':
+            converted = toKebabCase(data);
+            break;
+          case 'camelCase':
+            converted = toCamelCase(data);
+            break;
+          default: // Do nothing
+        }
+
+        return converted;
       }
     }
 
-    return converted;
+    return data;
   }
 };

Diff for: test/unit/JSONAPISerializer.test.js

@@ -2062,4 +2062,50 @@ describe('JSONAPISerializer', function() {
       done();
     });
   })
+
+ describe('convertCase', function() {
+  it('should convert an array of object to kebab-case', function() {
+    const jsonapiSerializer = new JSONAPISerializer();
+    const converted = jsonapiSerializer._convertCase(
+      [{
+        arrayOfObject: [
+          {
+            firstProperty: 'test',
+            secondProperty: null,
+            thirdProperty: 0
+          }
+        ],
+        arrayOfNumber: [1, 2, 3, 4, 5]
+      }],
+      'kebab-case'
+    );
+    
+    expect(converted).to.deep.equal([{
+      'array-of-object': [{ 'first-property': 'test', 'second-property': null, 'third-property': 0 }],
+      'array-of-number': [1, 2, 3, 4, 5]
+    }]);
+  });
+
+  it('should convert an object to kebab-case', function() {
+    const jsonapiSerializer = new JSONAPISerializer();
+    const converted = jsonapiSerializer._convertCase(
+      {
+        arrayOfObject: [
+          {
+            firstProperty: 'test',
+            secondProperty: null,
+            thirdProperty: 0
+          }
+        ],
+        arrayOfNumber: [1, 2, 3, 4, 5]
+      },
+      'kebab-case'
+    );
+      
+    expect(converted).to.deep.equal({
+      'array-of-object': [{ 'first-property': 'test', 'second-property': null, 'third-property': 0 }],
+      'array-of-number': [1, 2, 3, 4, 5]
+    });
+  });
+ }); 
 });