TypeError：无法读取 null 的属性“sendMessage”

Question

我正在尝试根据我在 slackClient.js 中的代码向我的新 Slackbot 发送带有预期行为的问候语来测试我的新 Slackbot：

'use strict'

const RtmClient = require('@slack/client').RtmClient;
const CLIENT_EVENTS = require('@slack/client').CLIENT_EVENTS;
const RTM_EVENTS = require('@slack/client').RTM_EVENTS;
let rtm = null;

function handleOnAuthenticated(rtmStartData) {
  console.log(`Logged in as ${rtmStartData.self.name} of team ${rtmStartData.team.name}, but not yet connected to a channel`);
}

function handleOnMessage(message) {
  console.log(message);
  // This will send the message 'this is a test message' to the channel identified by id 'C0CHZA86Q'
  rtm.sendMessage('this is a test message', message.channel, function messageSent() {
    // optionally, you can supply a callback to execute once the message has been sent
  });
}

function addAuthenticatedHandler(rtm, handler) {
  rtm.on(CLIENT_EVENTS.RTM.AUTHENTICATED, handler);
}

module.exports.init = function slackClient(bot_token, logLevel){
  const rtm = new RtmClient(bot_token);
  addAuthenticatedHandler(rtm, handleOnAuthenticated);
  rtm.on(RTM_EVENTS.MESSAGE, handleOnMessage)
  return rtm;
}

module.exports.addAuthenticatedHandler = addAuthenticatedHandler;

这是我得到的错误：

 rtm.sendMessage('this is a test message', message.channel, function messageSent() {
     ^

TypeError: Cannot read property 'sendMessage' of null

如果我理解正确，它告诉我我不能给 rtm 一个 null 值，但是我可以给它什么样的样板值以便我可以测试呢？

Answer 1

我发现了我的错误，我将 rtm 作为 const，然后是 let。所以我从 rtm = new RtmClient(bot_token); 中删除了 const然后继续添加 nlp，如下所示：

'use strict'

const RtmClient = require('@slack/client').RtmClient;
const CLIENT_EVENTS = require('@slack/client').CLIENT_EVENTS;
const RTM_EVENTS = require('@slack/client').RTM_EVENTS;
let rtm = null;
let nlp = null;

function handleOnAuthenticated(rtmStartData) {
  console.log(`Logged in as ${rtmStartData.self.name} of team ${rtmStartData.team.name}, but not yet connected to a channel`);
}

function handleOnMessage(message) {

  // This will send the message 'this is a test message' to the channel identified by id 'C0CHZA86Q'
  rtm.sendMessage('this is a test message', message.channel, function messageSent() {
    // optionally, you can supply a callback to execute once the message has been sent
  });
}

function addAuthenticatedHandler(rtm, handler) {
  rtm.on(CLIENT_EVENTS.RTM.AUTHENTICATED, handler);
}

module.exports.init = function slackClient(bot_token, logLevel, nlpClient){
  rtm = new RtmClient(bot_token);
  nlp = nlpClient;
  addAuthenticatedHandler(rtm, handleOnAuthenticated);
  rtm.on(RTM_EVENTS.MESSAGE, handleOnMessage)
  return rtm;
}

module.exports.addAuthenticatedHandler = addAuthenticatedHandler;