Delete all messages from a Slack channel

A feature that isn't natively available in Slack (at the time of writing)
Use this script to delete all messages from any slack channel, including #general.
You will need to be a Slack Administrator.

Demo

Quick Start

1. Clone the repository
2. Install dependencies with npm install or yarn install
3. Copy .env.example to .env
4. Create a Slack App (see Guide below)
5. Run the script and follow the prompts node index.js

Slack App Setup

To use the script you must create a Slack app that has the required permissions to view and delete messages. The steps are described below.

1. Log in to Slack App management
2. Click Create New App
3. Select From Scratch
4. Enter an App Name e.g. Deletor
5. Select the workspace to add the App to
6. Click Create App
7. On the left, click OAuth & Permissions
8. Scroll down to Scopes
9. Under Bot Token Scopes click Add an OAuth Scope and add channels:history, channels:read and chat:write in turn
10. Under User Token Scopes click Add an OAuth Scope and add chat:write
11. Scroll to the top and click Install to Workspace
12. Copy the User OAuth Token into the USER_TOKEN property in .env
13. Copy the Bot User OAuth Token into the BOT_TOKEN property in .env
14. Go to your Slack client and /invite @deletor into the channel you want to remove messages from
15. Run the script and follow the prompts node index.js

Rate Limiting

The script allows you to specify a custom rate limit if required. This is particularly useful on channels with a lot of messages. If you decide to use the Slack API defaults, then very quickly the delete attempts will be throttled until it's quite slow. By applying a custom rate limit, you can try and keep under the official rate limit radar. You can select which option to choose when running the script.

Troubleshooting

You're most likely to encounter errors relating to the tokens and scopes, for example cant_delete_message - double check steps 8-10 in the Slack App Setup above and also make sure you have correctly created your .env file, it should look like:

BOT_TOKEN=xoxb-222888608336-6599678687984-2Ufo177zpOIg06l1WVvyiiox
USER_TOKEN=xoxp-222888608336-223470001299-6589549747649-f9cb406156c663158de29d07566dfeb4

After Use

I highly recommend you remove the app from your channel and delete the App from the Slack control panel. At the very least, revoke the tokens!