Discord.js 未处理的PromisejectionWarning:TypeError:无法读取属性'；从'开始；未定义的

我是discord bot开发的新手，遇到如下错误：

WOKCommands > Loaded 12 commands.
WOKCommands > Loaded 3 listeners.
(node:14932) **UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'startsWith' of undefined**
    at module.exports (C:\Users\melih\Desktop\lechsbott\features\message.js:4:25)
    at FeatureHandler.registerFeature (C:\Users\melih\Desktop\lechsbott\node_modules\wokcommands\dist\FeatureHandler.js:107:13)
    at FeatureHandler.<anonymous> (C:\Users\melih\Desktop\lechsbott\node_modules\wokcommands\dist\FeatureHandler.js:161:28)    
    at step (C:\Users\melih\Desktop\lechsbott\node_modules\wokcommands\dist\FeatureHandler.js:52:23)
    at Object.next (C:\Users\melih\Desktop\lechsbott\node_modules\wokcommands\dist\FeatureHandler.js:33:53)
    at fulfilled (C:\Users\melih\Desktop\lechsbott\node_modules\wokcommands\dist\FeatureHandler.js:24:58)
    at processTicksAndRejections (internal/process/task_queues.js:93:5)

---

消息。内容

未定义。可能以错误的顺序传递了

（Discord、client、message）

。在将模块作为命令加载的主文件中，可能没有传递正确的变量

module.exports = (Discord, client, message) =>{
    const fs = 'l!';
    const prefix = process.env.PREFIX;
    if(!message.content.startsWith(prefix) || message.author.bot) return;
    
    const args = message.content.slice(prefix.length).split(/ +/);
    const cmd = args.shift().toLowerCase();

    const command = client.commands.get(cmd);

    if(command) command.execute(client, message, args, Discord);
}