Code

const discord = require("discord.js");
const botConfig = require("./botconfig.json");

const client = new discord.Client();
client.login(botConfig.token);

client.on("ready", async () => {

    console.log(`${client.user.username} is online`);
    client.user.setActivity("!help", {type: "Playing"});

});

client.on("message", async message =>{

    if(message.author.bot) return;

    if(message.channel.type == "dm") return;

    var prefix = botConfig.prefix;

    var messageArray = mesage.content.spit(" ");

    var command = messageArray[0];

    if(command === `${prefix}hallo`){
        return message.channel.send("Hoi!");
    }

});


Error:

(node:28364) UnhandledPromiseRejectionWarning: ReferenceError: mesage is not defined
    at Client.<anonymous> (A:\Discord_Bot\bot\index.js:22:24)
    at Client.emit (events.js:315:20)
    at MessageCreateAction.handle (A:\Discord_Bot\bot\node_modules\discord.js\src\client\actions\MessageCreate.js:31:14)
    at Object.module.exports [as MESSAGE_CREATE] (A:\Discord_Bot\bot\node_modules\discord.js\src\client\websocket\handlers\MESSAGE_CREATE.js:4:32)
    at WebSocketManager.handlePacket (A:\Discord_Bot\bot\node_modules\discord.js\src\client\websocket\WebSocketManager.js:384:31)
    at WebSocketShard.onPacket (A:\Discord_Bot\bot\node_modules\discord.js\src\client\websocket\WebSocketShard.js:444:22)
    at WebSocketShard.onMessage (A:\Discord_Bot\bot\node_modules\discord.js\src\client\websocket\WebSocketShard.js:301:10)
    at WebSocket.onMessage (A:\Discord_Bot\bot\node_modules\ws\lib\event-target.js:132:16)
    at WebSocket.emit (events.js:315:20)
    at Receiver.receiverOnMessage (A:\Discord_Bot\bot\node_modules\ws\lib\websocket.js:825:20)
(Use `node --trace-warnings ...` to show where the warning was created)
(node:28364) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:28364) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are
not handled will terminate the Node.js process with a non-zero exit code.