Click the first reaction in an open Slack channel

agree.js

// How to use: open Console (View -> Developer -> Developer Tools -> Console)
// and paste one of the following:

/**
 * Agree with ~first~ reaction in active Slack channel, poll every 10 seconds.
 **/ 
function clickFirstReaction() {
    $("div.c-reaction_bar > button:nth-child(1):not(.c-reaction--reacted)").click()
}
var timerID = setInterval(clickFirstReaction, 10000);

// -- //

/**
 * Agree with ~every~ reaction in active Slack channel, poll every 10 seconds.
 **/ 
function clickEveryReaction() {
    $("div > button.c-button-unstyled.c-reaction:not(.c-reaction--reacted) > span.emoji-outer.emoji-sizer").click()
}
var timerID = setInterval(clickEveryReaction, 10000);