feat(secure-storage): Add Secure Storage Wrapper (#347)

* Add SecureStorage plugin.

* Add SecureStorage plugin.

* Added create() and removed init() to provide more consistency to ionic-native plugins.
Edited comments to reflect changes.

* Removed init and comment edit.

src/index.ts

@@ -62,6 +62,7 @@ import {Printer} from './plugins/printer';
 import {Push} from './plugins/push';
 import {SafariViewController} from './plugins/safari-view-controller';
 import {Screenshot} from './plugins/screenshot';
+import {SecureStorage} from './plugins/securestorage';
 import {Sim} from './plugins/sim';
 import {SMS} from './plugins/sms';
 import {SocialSharing} from './plugins/socialsharing';
@@ -139,6 +140,7 @@ export {
   OneSignal,
   PinDialog,
   Screenshot,
+  SecureStorage,
   SocialSharing,
   Sim,
   Splashscreen,
@@ -211,6 +213,7 @@ window['IonicNative'] = {
   PinDialog: PinDialog,
   SafariViewController: SafariViewController,
   Screenshot: Screenshot,
+  SecureStorage: SecureStorage,
   Sim: Sim,
   SMS: SMS,
   SocialSharing: SocialSharing,

src/plugins/securestorage.ts

@@ -0,0 +1,92 @@
+import { CordovaInstance, Plugin } from './plugin';
+
+declare var cordova: any;
+
+/**
+ * @name Secure Storage
+ * @description
+ * This plugin gets, sets and removes key,value pairs from a device's secure storage.
+ *
+ * Requires Cordova plugin: `cordova-plugin-secure-storage`. For more info, please see the [Cordova Secure Storage docs](https://github.com/Crypho/cordova-plugin-secure-storage).
+ *
+ * @usage
+ * 
+ * ```typescript
+ * import { SecureStorage } from 'ionic-native';
+ *
+ * let secureStorage: SecureStorage = new SecureStorage();
+ * secureStorage.create('my_store_name')
+ *  .then(
+ *    () => console.log('Success'), 
+ *    error => console.log(error);
+ * );
+ * 
+ * secureStorage.get('myitem')
+ *  .then(
+ *    data => console.log(data),
+ *    error => console.log(error)
+ * );
+ * 
+ * secureStorage.set('myitem', 'myvalue')
+ *  .then(
+ *    data => console.log(data),
+ *    error => console.log(error)
+ * );
+ * 
+ * secureStorage.remove('myitem')
+ * .then(
+ *    data => console.log(data),
+ *    error => console.log(error)
+ * );
+ * ```
+ */
+@Plugin({
+  plugin: 'cordova-plugin-secure-storage',
+  pluginRef: 'plugins.securestorage',
+  repo: 'https://github.com/Crypho/cordova-plugin-secure-storage',
+  platforms: ['Android', 'iOS', 'Windows Phone', 'Browser']
+})
+export class SecureStorage {
+
+  private _objectInstance: any;
+
+  constructor()  {}
+
+  /**
+   * Creates a namespaced storage. 
+   * @param store {string}
+   */
+  create(store: string): Promise<any> {
+    return new Promise((res, rej) => {
+      this._objectInstance = new cordova.plugins.SecureStorage(res, rej, store);
+    });
+  }
+
+  /**
+   * Gets a stored item
+   * @param reference {string}
+   */
+ @CordovaInstance({
+    callbackOrder: 'reverse'
+  })
+  get(reference: string): Promise<any> { return; }
+
+  /**
+   * Stores a value
+   * @param reference {string}
+   * @param value {string}
+   */
+ @CordovaInstance({
+    callbackOrder: 'reverse'
+  })
+  set(reference: string, value: string): Promise<any> { return; }
+
+  /**
+   * Removes a single stored item
+   * @param reference {string}
+   */
+ @CordovaInstance({
+    callbackOrder: 'reverse'
+  })
+  remove(reference: string): Promise<any> { return; }
+}