Add getAllKeys Method to SyncStorage (#5)

* Add getAllKeys method

* Add update method

* Add push method

* Add update to readme

* Fix small grammatical problem in error message of update method

* Add test for push update and getAllKeys methods

* Add test for push error for non Array value

* Refactoring
Make handleError work with single argument

* Fix flow for second argument in handleError

* Remove push and update functions

* Update readme, fixing small issue with tests.

README.md

@@ -93,3 +93,13 @@ SyncStorage.remove('foo')
     console.log(error);
   });
 ```
+
+#### getAllKeys()
+
+returns an array from all the keys.
+
+ ```js
+ SyncStorage.set('foo', 'bar');
+ SyncStorage.set('boo', 'baz');
+ console.log(SyncStorage.getAllKeys()) // ['foo', 'boo']
+```

src/__tests__/index.test.js

@@ -39,3 +39,11 @@ test("Can update an item", () => {
   SyncStorage.saveItem(['bar', 'baz']);
   expect(SyncStorage.get('bar')).toBe('baz');
 });
+
+test('Can get all keys from storage', () => {
+  SyncStorage.set('foo', 'bar');
+  const all_keys = SyncStorage.getAllKeys();
+  expect(all_keys)
+    .toEqual(expect.arrayContaining(['foo']));
+});
+

src/helpers/handleError.js

@@ -1,7 +1,12 @@
 // @flow
 
-function handleError(func: string, param: string): Promise<string> {
-  const message = `${func}() requires at least ${param} as its first parameter.`;
+function handleError(func: string, param: ?string): Promise<string> {
+  let message;
+  if (!param) {
+    message = func;
+  } else {
+    message = `${func}() requires at least ${param} as its first parameter.`;
+  }
   console.warn(message); // eslint-disable-line no-console
   return Promise.reject(message);
 }

src/index.js

@@ -48,6 +48,10 @@ class SyncStorage {
     this.data.set(item[0], value);
     this.loading = false;
   }
+
+  getAllKeys(): Array<*> {
+    return Array.from(this.data.keys());
+  }
 }
 
 const syncStorage = new SyncStorage();