如何克服 Node.js 中的"类型错误：类扩展值未定义不是构造函数或 null"错误？

Question

>我正在尝试构建一个机器人。所以在一个 Node.js 文件中，我在使用 ActivityHandler 时收到以下错误 - TypeError: Class extends value undefined is not a constructor or null

这是我正在使用的代码 -

const { ActivityHandler } = require('botbuilder');
const { LuisRecognizer, QnAMaker } = require('botbuilder-ai');
class DispatchBot extends ActivityHandler {
    constructor(logger) {
        super();
        if (!logger) {
            logger = console;
            logger.log('[DispatchBot]: logger not passed in, defaulting to console');
        }
        const dispatchRecognizer = new LuisRecognizer({
            applicationId: process.env.LuisAppId,
            endpointKey: process.env.LuisAPIKey,
            endpoint: `https://${ process.env.LuisAPIHostName }.api.cognitive.microsoft.com`
        }, {
            includeAllIntents: true,
            includeInstanceData: true
        }, true);
        const qnaMaker = new QnAMaker({
            knowledgeBaseId: process.env.QnAKnowledgebaseId,
            endpointKey: process.env.QnAAuthKey,
            host: process.env.QnAEndpointHostName
        });
        this.logger = logger;
        this.dispatchRecognizer = dispatchRecognizer;
        this.qnaMaker = qnaMaker;
        this.onMessage(async (context, next) => {
            this.logger.log('Processing Message Activity.');
            const recognizerResult = await dispatchRecognizer.recognize(context);
            const intent = LuisRecognizer.topIntent(recognizerResult);
            await this.dispatchToTopIntentAsync(context, intent, recognizerResult);
            await next();
        });
        this.onMembersAdded(async (context, next) => {
            const welcomeText = 'Type a greeting or a question about the weather to get started.';
            const membersAdded = context.activity.membersAdded;
            for (let member of membersAdded) {
                if (member.id !== context.activity.recipient.id) {
                    await context.sendActivity(`Welcome to Dispatch bot ${ member.name }. ${ welcomeText }`);
                }
            }
            await next();
        });
    }
    async dispatchToTopIntentAsync(context, intent, recognizerResult) {
        switch (intent) {
        case 'l_luis':
            await this.processLuis(context, recognizerResult.luisResult);
            break;
        case 'q_sample-qna':
            await this.processSampleQnA(context);
            break;
        default:
            this.logger.log(`Dispatch unrecognized intent: ${ intent }.`);
            await context.sendActivity(`Dispatch unrecognized intent: ${ intent }.`);
            break;
        }
    }
}
module.exports.DispatchBot = DispatchBot;

错误-

class DispatchBot extends ActivityHandler {
                          ^
TypeError: Class extends value undefined is not a constructor or null

那么有什么方法可以避免这种问题呢？

Answer 1

我的问题通过卸载botbuilder软件包并重新安装就解决了。