diff --git a/src/preload/index.ts b/src/preload/index.ts
index 46b96bf..8fc5f6f 100644
--- a/src/preload/index.ts
+++ b/src/preload/index.ts
@@ -1,25 +1,25 @@
 import { contextBridge, ipcRenderer } from 'electron'
 
 // Whitelist of valid channels used for IPC communication (Send message from Renderer to Main)
-const mainAvailChannels = ['msgRequestGetVersion', 'msgOpenExternalLink']
-const rendererAvailChannels = ['msgReceivedVersion']
+const mainAvailChannels: string[] = ['msgRequestGetVersion', 'msgOpenExternalLink']
+const rendererAvailChannels: string[] = ['msgReceivedVersion']
 
 contextBridge.exposeInMainWorld('mainApi', {
-  send: (channel, ...data) => {
+  send: (channel: string, ...data: any[]): void => {
     if (mainAvailChannels.includes(channel)) {
       ipcRenderer.send.apply(null, [channel, ...data])
     } else {
       throw new Error(`Send failed: Unknown ipc channel name: ${channel}`)
     }
   },
-  receive: (channel, cbFunc) => {
+  receive: (channel: string, cbFunc: Function): void => {
     if (rendererAvailChannels.includes(channel)) {
       ipcRenderer.on(channel, (event, ...args) => cbFunc(event, ...args))
     } else {
       throw new Error(`Receive failed: Unknown ipc channel name: ${channel}`)
     }
   },
-  invoke: async (channel, ...data) => {
+  invoke: async (channel: string, ...data: any[]): Promise<any> => {
     if (mainAvailChannels.includes(channel)) {
       const result = await ipcRenderer.invoke.apply(null, [channel, ...data])
       return result