Store the message count for each member

You need to store the number of messages each member posts. To make sure your code works even if your Bot restarts, you should use the Root API's KeyValueStore type. Root automatically backs up and restores the key-value store, so your data is persistent.

1. Store the count

1. Open the file src/example.ts.

2. Locate the onMessage function.

3. Remove the echo functionality (listening for /echo and responding).

4. Add the following lines of code to onMessage after the check for system messages. The appData property is the KeyValueStore object. The update method is perfect for this use case, here's how it works:

   • Updates a value associated with a key.
   • You must include a transformation function to perform the update: the old value is retrieved, the function is called with the old value, the function's return value is used as the new value in the key-value store.
   • If the key does not exist, this conceptually becomes a set operation. The transformation function is applied to the default and the result becomes the value in the set operation.

   const count: number = await rootServer.dataStore.appData.update(evt.userId, (val:number) => val + 1, 0);
   console.log(evt.userId + " " + count);

2. Test and clean up

1. Build and run your Bot.

2. Use the Root native client to post messages to community channels. Verify that the console.log message shows 1 on your first message, 2 on your second, etc. This indicates the storage and update method are working correctly.

3. Stop your Bot.

4. Delete the rootsdk.sqlite3 file from your Bot's project folder. The file contains the key-value store data, so deleting the file will reset the counts.