How to Plan

When you're building an event source application on AtomOne you'll likely want to lay out the necessary building blocks for your individual application.

It requires thinking in a slightly different way, but it's quite straight forward.

Understand Constraints

• Memos can only be 512 bytes

• Memos can be pruned depending on the API provider, not all API providers run nodes with all history maintained

• What is posted on-chain is there forever, nothing can remove it. Only an action can hide it from the client view

Plan the Memos

The first step you should take is layout all of the necessary memos you're going to be using.

Here's an example of a forum application.

// Create Thread
forum.Create("title", "content")

// Reply to Thread
forum.Reply("thread_hash", "content")

// Delete Reply (If Owner)
forum.ReplyDelete("thread_hash", "msg_hash")

// Delete Thread (If Owner)
froum.ThreadDelete("thread_hash")

// Upvote Message / Thread
forum.Upvote("thread_hash", "optional_msg_hash");

// Remove Upvote from Message / Thread
forum.Unvote("thread_hash", "optiona_msg_hash")

All of the above allows you to easily construct a forum with threads, replies, and a simple upvote system.

Build the Memos

Once you have the memos built out, it's recommended to build all of the necessary functional actions to modify the state.

Use the Constructor Library to easily bind actions to functions.

Below is an example from a Todo List Application:

const constructor = new ChronoConstructor<{ [hash: string]: string }>();

// todo.Add("this is my todo list item")
constructor.addAction('Add', (dataSet, action) => {
  const [arg1] = extractMemoContent(action.memo, 'example.add');
  if (!arg1) {
    console.warn(`Skipped ${action.hash}, content is missing args`);
    return;
  }

  dataSet[action.hash] = arg1;
});

// todo.Remove("hash_from_tx_for_add")
constructor.addAction('Remove', (dataSet, action) => {
 const [hash] = extractMemoContent(action.memo, 'example.add');
  if (!hash) {
    console.warn(`Skipped ${action.hash}, hash is missing from action`);
    return;
  }

  delete dataSet[hash];
});

async function update() {
  // Note that actionList is not defined, and assumes you're pulling from a localhost instance.
  // Additionally actionList is either the full list, or partial
  // Existing state is either a new instance, or an existing instance
  state.value = await constructor.parse(actionList, existingState);
}

update();

Deploy a ChronoSync Instance

There's a few different flavors of ChronoSync that will allow you to start indexing memos.

However, how you serve them is up to you and your individual needs.

I highly recommend the Postgres ChronoSync mixed with PostgREST for a quick startup.

Learn more about ChronoSync.