/conversations.join

{
  "channel": {
    "created": 1449252889,
    "creator": "U061F7AUR",
    "id": "C061EG9SL",
    "is_archived": false,
    "is_channel": true,
    "is_ext_shared": false,
    "is_general": true,
    "is_group": false,
    "is_im": false,
    "is_member": true,
    "is_mpim": false,
    "is_org_shared": false,
    "is_pending_ext_shared": false,
    "is_private": false,
    "is_shared": false,
    "name": "general",
    "name_normalized": "general",
    "pending_shared": [],
    "previous_names": [],
    "purpose": {
      "creator": "",
      "last_set": 0,
      "value": "For widget discussion"
    },
    "topic": {
      "creator": "",
      "last_set": 0,
      "value": "Which widget do you worry about?"
    },
    "unlinked": 0
  },
  "ok": true,
  "response_metadata": {
    "warnings": [
      "already_in_channel"
    ]
  },
  "warning": "already_in_channel"
}