Convert SettingsHandler to TS

src/settings/handlers/SettingsHandler.ts

@@ -1,6 +1,6 @@
 /*
 Copyright 2017 Travis Ralston
-Copyright 2019 New Vector Ltd.
+Copyright 2019, 2020 The Matrix.org Foundation C.I.C.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -28,7 +28,7 @@ export default class SettingsHandler {
      * @param {String} roomId The room ID to read from, may be null.
      * @returns {*} The setting value, or null if not found.
      */
-    getValue(settingName, roomId) {
+    public getValue(settingName: string, roomId: string): any {
         console.error("Invalid operation: getValue was not overridden");
         return null;
     }
@@ -44,7 +44,7 @@ export default class SettingsHandler {
      * @param {*} newValue The new value for the setting, may be null.
      * @returns {Promise} Resolves when the setting has been saved.
      */
-    setValue(settingName, roomId, newValue) {
+    public setValue(settingName: string, roomId: string, newValue): Promise<void> {
         console.error("Invalid operation: setValue was not overridden");
         return Promise.reject();
     }
@@ -56,7 +56,7 @@ export default class SettingsHandler {
      * @param {String} roomId The room ID to check in, may be null
      * @returns {boolean} True if the setting can be set by the user, false otherwise.
      */
-    canSetValue(settingName, roomId) {
+    public canSetValue(settingName: string, roomId: string): boolean {
         return false;
     }
 
@@ -64,7 +64,7 @@ export default class SettingsHandler {
      * Determines if this level is supported on this device.
      * @returns {boolean} True if this level is supported on the current device.
      */
-    isSupported() {
+    public isSupported(): boolean {
         return false;
     }
 }