sendMessage API returns 'invalid channel id' with Docs examples

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Description

When calling rtm.sendMessage('test', ...) with a username like @test, or userid provided from message.user (like U3B4XADP9) it does not work. Instead a SlackRTMError is returned with ‘invalid channel id’.

The only way I’ve found to DM a user or send a message to a chat is to hardcode the channel found from message.channel (like G3BBUJ7HE).

The docs make it sound like this should work: https://slackapi.github.io/node-slack-sdk/bots#posting-a-message

However the docs here: https://api.slack.com/methods/chat.postMessage discuss Channels and explain some of these issues.

So what’s broken? Is it the API, or are the docs inconsistent?

[jwulf]

The docs are broken.

Put this in the README.md example:

let channel;

rtm.on(CLIENT_EVENTS.RTM.AUTHENTICATED,  (rtmStartData) => {
  for (const c of rtmStartData.channels) {
	  if (c.is_member && c.name ==='general') { channel = c.id }
  }
  console.log(`Logged in as ${rtmStartData.self.name} of team ${rtmStartData.team.name}, but not yet connected to a channel`);
});

Then the example will work with a copy and paste.

[DEGoodmanWilson]

A fair question, thank you for raising it! At the lowest level, the RTM API only allows you to specify a channel/group/DM id. You cannot use a channel name, a user name, or a user id. This is clearly a problem with the documentation for this project.

Please note that chat.postMessage is a different API from the RTM API—and it is much more permissive about what it will accept.