Slack: Get a list of your channels (excluding DMs, group chats, and archived/private channels)

get_channels.js

// Open up the Slack Developer Tools by entering "/slackdevtools"
// in the message input.

// First, run this. The client will reload.
slackDebug.enable()

// Then, get channels. See "filterChannels" to remove channels
// beginning with a certain prefix.
(function getMyChannels() {
  const allChannels = slackDebug.storeInstance.getStateByTeamId(slackDebug.activeTeamId).channels.__proto__
  let myChannels = []
  
  // Filter out channels beginnging with...
  let filterChannels = ['ir-', 'bc-', 'ex-']

  for (const key of Object.keys(allChannels)) {
    const channel = allChannels[key]

    // No DMs, MPDMs, etc
    if (!channel.is_channel || !channel.is_member) continue
    // No channels nobody can join
    if (channel.is_archived || channel.is_private) continue
    // No garbage
    if (channel.isNonExistent || channel.isUnknown || channel.fromAnotherTeam) continue
    // Filter prefixes
    if (filterChannels.find((prefix) => channel.name.startsWith(prefix))) {
      continue
    }

    myChannels.push({
      name: channel.name,
      topic: channel.topic?.value,
      purpose: channel.purpose?.value,
    })
  }

  myChannels.sort((a, b) => a.name.localeCompare(b.name))
  
  // Make a new window
  const channelWindow = window.open('about:blank')
  const list = channelWindow.document.createElement('ul')
  channelWindow.document.body.style.fontFamily = `-apple-system, BlinkMacSystemFont` 
  channelWindow.document.body.appendChild(list)

  for (const channel of myChannels) {
    const li = channelWindow.document.createElement('li')
    const small = channelWindow.document.createElement('small')
    const name = `#${channel.name}`
    const purpose = channel.purpose ? ` (${channel.purpose})` : ``
    small.appendChild(channelWindow.document.createTextNode(purpose))

    li.appendChild(channelWindow.document.createTextNode(name))
    li.appendChild(small)
    list.appendChild(li)
  }
})()

// Then, disable SlackDebug. The client will reload.
slackDebug.disable()