Hubot-slack: What is the correct way to add a reaction to a heard message?

[deathau]

Description

What is the correct way to add a reaction to a heard message?

What type of issue is this? (place an x in one of the [ ])

• [ ] bug
• [ ] enhancement (feature request)
• [x] question
• [ ] documentation related
• [ ] testing related
• [ ] discussion

Requirements (place an x in each of the [ ])

• [x] I've read and understood the Contributing guidelines and have done my best effort to follow them.
• [x] I've read and agree to the Code of Conduct.
• [x] I've searched for any related issues and avoided creating a duplicate issue.

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Question

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Reproducible in:

hubot-slack version: 4.5.4

node version: 8.11.3

Question

I was attempting to follow the example in the documentation here: https://slackapi.github.io/hubot-slack/basic_usage#message-reactions which seems to use the WebClient to add a reaction. Rather than responding to a reaction like that example does, I'm trying to respond to a message.
Here is the code I have so far:

{WebClient} = require "@slack/client"

module.exports = (robot) ->
    if robot.adapter.options && robot.adapter.options.token
        web = new WebClient robot.adapter.options.token

        robot.hear /Monitor is DOWN/i, (msg) ->
            robot.logger.info "attempting to react. name:'serverdown', channel: #{msg.message.rawMessage.channel}, timestamp: #{msg.message.rawMessage.ts}"
            web.reactions.add
                name: 'serverdown',
                channel: "#{msg.message.rawMessage.channel}",
                timestamp: "#{msg.message.rawMessage.ts}"

But I keep getting errors like the following:

error: Response not OK:  invalid_array_arg
Unhandled rejection Error: invalid_array_arg

Am I doing something wrong, or is there a bug here?

[aoberoi]

@deathau: the code you're using looks correct to me, but there's one gotcha that's actually noted in this section: https://slackapi.github.io/hubot-slack/basic_usage#using-the-slack-web-api. that is, you should npm install @slack/client in your app in order to get this to work. the problem is that there's an older version of @slack/client available to node since hubot-slack depends on it, but the latest version is what you want to use. let me know if that fixes the issue 😄

[deathau]

Awesome, must have missed that in the docs. Thanks for not just providing the solution, but explaining why