diff --git a/src/preload.js b/src/preload.ts
similarity index 86%
rename from src/preload.js
rename to src/preload.ts
index 64849f5..491e8b9 100644
--- a/src/preload.js
+++ b/src/preload.ts
@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-const { ipcRenderer, desktopCapturer, contextBridge } = require('electron');
+import { ipcRenderer, desktopCapturer, contextBridge, IpcRendererEvent, SourcesOptions } from 'electron';
 
 // Expose only expected IPC wrapper APIs to the renderer process to avoid
 // handing out generalised messaging access.
@@ -39,21 +39,21 @@ const CHANNELS = [
 contextBridge.exposeInMainWorld(
     "electron",
     {
-        on(channel, listener) {
+        on(channel: string, listener: (event: IpcRendererEvent, ...args: any[]) => void) {
             if (!CHANNELS.includes(channel)) {
                 console.error(`Unknown IPC channel ${channel} ignored`);
                 return;
             }
             ipcRenderer.on(channel, listener);
         },
-        send(channel, ...args) {
+        send(channel: string, ...args: any[]) {
             if (!CHANNELS.includes(channel)) {
                 console.error(`Unknown IPC channel ${channel} ignored`);
                 return;
             }
             ipcRenderer.send(channel, ...args);
         },
-        async getDesktopCapturerSources(options) {
+        async getDesktopCapturerSources(options: SourcesOptions) {
             const sources = await desktopCapturer.getSources(options);
             const desktopCapturerSources = [];