Fix util.js and add tests

app/javascript/util/util.js

@@ -1,11 +1,11 @@
-import { camelCase, isPlainObject, forEach, mapKeys, mapValues } from 'lodash';
+// @flow
+import { camelCase, mapKeys, mapValues } from 'lodash';
 
-export function camelizeKeys<T>(obj: T): T {
-  if (isPlainObject(obj)) {
-    let aux = mapKeys(obj, (_, key: string) => camelCase(key));
-    return mapValues(aux, camelizeKeys);
-  } else if (Array.isArray(obj)) {
-    return obj.map((val: mixed) => camelizeKeys(val));
+export function camelizeKeys<T>(obj: T): Object | T {
+  if (Array.isArray(obj)) return obj.map(v => camelizeKeys(v));
+  if (typeof obj === 'object') {
+    const camelCased = mapKeys(obj, (v, k: string): string => camelCase(k));
+    return mapValues(camelCased, (v: Object) => camelizeKeys(v));
   }
   return obj;
 }

app/javascript/util/util.test.js

@@ -0,0 +1,77 @@
+// @flow
+import { camelizeKeys } from './util';
+import { mapValues, mapKeys } from 'lodash';
+
+const fixture: Object = {
+  camelCaseKey: 'lorem',
+  snake_case_key: 'ipsum',
+  'kebab-case-key': 'dolor',
+  PascalCaseKey: 'sit',
+  'Strangely-formatted_KeyName': 'Strangely-formatted_KeyValue',
+  array_with_objects: [
+    { snake_case: 'snake_case' },
+    { 'kebab-case': 'kebab-case' },
+  ],
+  camel_case_subgroup: {
+    number_key: 1,
+    letter_key: 'a',
+    array_key: [0, 1, 2],
+    object_key: {
+      'kebab-case-key': 'value',
+    },
+  },
+};
+
+it('keeps camelCase keys intact', () => {
+  expect(camelizeKeys(fixture)).toHaveProperty('camelCaseKey');
+  expect(camelizeKeys(fixture)).toHaveProperty('arrayWithObjects');
+});
+
+it('converts snake_case keys to camelCase', () => {
+  expect(camelizeKeys(fixture)).toHaveProperty('snakeCaseKey', 'ipsum');
+});
+
+it('converts kebab-case keys to camelCase', () => {
+  expect(camelizeKeys(fixture)).toHaveProperty('kebabCaseKey', 'dolor');
+});
+
+it('converts PascalCase keys to camelCase', () => {
+  expect(camelizeKeys(fixture)).toHaveProperty('pascalCaseKey', 'sit');
+});
+
+it('converts Stragely-formatted_KeyNames to camelCase', () => {
+  expect(camelizeKeys(fixture)).toHaveProperty(
+    'strangelyFormattedKeyName',
+    'Strangely-formatted_KeyValue'
+  );
+});
+
+it('converts array items', () => {
+  const camelizedArray = camelizeKeys(fixture).arrayWithObjects;
+  expect(camelizedArray[0]).toHaveProperty('snakeCase', 'snake_case');
+  expect(camelizedArray[1]).toHaveProperty('kebabCase', 'kebab-case');
+});
+
+it('converts nested keys', () => {
+  expect(camelizeKeys(fixture).camelCaseSubgroup).toHaveProperty('numberKey');
+});
+
+it('converts deeply nested keys', () => {
+  const { camelCaseSubgroup } = camelizeKeys(fixture);
+  expect(camelCaseSubgroup.objectKey).toHaveProperty('kebabCaseKey');
+});
+
+describe('values', () => {
+  it('keeps strings intact', () => {
+    expect(camelizeKeys(fixture).camelCaseKey).toBe('lorem');
+  });
+
+  it('keeps numbers intact', () => {
+    const { camelCaseSubgroup } = camelizeKeys(fixture);
+    expect(camelCaseSubgroup.numberKey).toBe(1);
+  });
+
+  it('keeps arrays intact', () => {
+    expect(Array.isArray(camelizeKeys(fixture).arrayWithObjects)).toBeTruthy();
+  });
+});