Node.js TypeError：Wit不是一个构造函数

如何在执行node-wit和wit.ai文档给出的代码时解决来自Node.js的“机智不是构造函数”错误。

// Setting up our bot const wit = new Wit(WIT_TOKEN, actions); 

我通过升级和降级npm / node版本来尝试所有的方法，但没有运气。

更新：请find我使用的index.js源码，
我需要改变这个吗？

 module.exports = { Logger: require('./lib/logger.js').Logger, logLevels: require('./lib/logger.js').logLevels, Wit: require('./lib/wit.js').Wit, } 'use strict'; var express = require('express'); var bodyParser = require('body-parser'); var request = require('request'); const Logger = require('node-wit').Logger; const levels = require('node-wit').logLevels; var app = express(); app.use(bodyParser.urlencoded({extended: false})); app.use(bodyParser.json()); app.listen((process.env.PORT || 3000)); //const Wit = require('node-wit').Wit; const WIT_TOKEN = process.env.WIT_TOKEN; const FB_PAGE_TOKEN = process.env.FB_PAGE_TOKEN; const Wit = require('node-wit').Wit; // Server frontpage app.get('/', function (req, res) { debugger; res.send('This is TestBot Server'); }); // Messenger API specific code // See the Send API reference // https://developers.facebook.com/docs/messenger-platform/send-api-reference const fbReq = request.defaults({ uri: 'https://graph.facebook.com/me/messages', method: 'POST', json: true, qs: { access_token: FB_PAGE_TOKEN }, headers: {'Content-Type': 'application/json'}, }); const fbMessage = (recipientId, msg, cb) => { const opts = { form: { recipient: { id: recipientId, }, message: { text: msg, }, }, }; fbReq(opts, (err, resp, data) => { if (cb) { cb(err || data.error && data.error.message, data); } }); }; // See the Webhook reference // https://developers.facebook.com/docs/messenger-platform/webhook-reference const getFirstMessagingEntry = (body) => { const val = body.object == 'page' && body.entry && Array.isArray(body.entry) && body.entry.length > 0 && body.entry[0] && body.entry[0].id === FB_PAGE_ID && body.entry[0].messaging && Array.isArray(body.entry[0].messaging) && body.entry[0].messaging.length > 0 && body.entry[0].messaging[0] ; return val || null; }; // Wit.ai bot specific code // This will contain all user sessions. // Each session has an entry: // sessionId -> {fbid: facebookUserId, context: sessionState} const sessions = {}; const findOrCreateSession = (fbid) => { var sessionId; // Let's see if we already have a session for the user fbid Object.keys(sessions).forEach(k => { if (sessions[k].fbid === fbid) { // Yep, got it! sessionId = k; } }); if (!sessionId) { // No session found for user fbid, let's create a new one sessionId = new Date().toISOString(); sessions[sessionId] = {fbid: fbid, context: {}}; } return sessionId; }; // Our bot actions const actions = { say(sessionId, context, message, cb) { // Our bot has something to say! // Let's retrieve the Facebook user whose session belongs to const recipientId = sessions[sessionId].fbid; if (recipientId) { // Yay, we found our recipient! // Let's forward our bot response to her. fbMessage(recipientId, message, (err, data) => { if (err) { console.log( 'Oops! An error occurred while forwarding the response to', recipientId, ':', err ); } // Let's give the wheel back to our bot cb(); }); } else { console.log('Oops! Couldn\'t find user for session:', sessionId); // Giving the wheel back to our bot cb(); } }, merge(sessionId, context, entities, message, cb) { cb(context); }, error(sessionId, context, error) { console.log(error.message); }, // You should implement your custom actions here // See https://wit.ai/docs/quickstart }; const wit = new Wit(WIT_TOKEN, actions); // Message handler app.post('/webhook', (req, res) => { // Parsing the Messenger API response // Setting up our bot //const wit = new Wit(WIT_TOKEN, actions); const messaging = getFirstMessagingEntry(req.body); if (messaging && messaging.message && messaging.message.text) { // Yay! We got a new message! // We retrieve the Facebook user ID of the sender const sender = messaging.sender.id; // We retrieve the user's current session, or create one if it doesn't exist // This is needed for our bot to figure out the conversation history const sessionId = findOrCreateSession(sender); // We retrieve the message content const msg = messaging.message.text; const atts = messaging.message.attachments; if (atts) { // We received an attachment // Let's reply with an automatic message fbMessage( sender, 'Sorry I can only process text messages for now.' ); } else if (msg) { // We received a text message // Let's forward the message to the Wit.ai Bot Engine // This will run all actions until our bot has nothing left to do wit.runActions( sessionId, // the user's current session msg, // the user's message sessions[sessionId].context, // the user's current session state (error, context) => { if (error) { console.log('Oops! Got an error from Wit:', error); } else { // Our bot did everything it has to do. // Now it's waiting for further messages to proceed. console.log('Waiting for futher messages.'); // Based on the session state, you might want to reset the session. // This depends heavily on the business logic of your bot. // Example: // if (context['done']) { // delete sessions[sessionId]; // } // Updating the user's current session state sessions[sessionId].context = context; } } ); } } res.sendStatus(200); }); 

Answer 1

你的问题有两个典型的原因，要么忘记require你的模块，要么忘记npm install它。 检查你是否：

1. 忘了require('node-wit')并从返回的对象中获取构造函数：
   • const Wit = require('node-wit').Wit
2. 正确要求Wit但忘了npm install node-wit

Answer 2

对于每个使用messenger.js作为你的index.js的人来说：

 const Wit = require('./lib/wit'); const log = require('./lib/log'); 

Answer 3

请检查node_modules目录中的node-wit软件包。

如果node-wit存在，那么在尝试创build它的实例之前请先要求它。

 const {Wit} = require('node-wit'); witHandler = new Wit({ accessToken: accessToken });