Then idea would be that one could declare scope on a node. Child nodes would be executed in that scope and variables set and fetched in the scope. If one would like to reset the scope one could start a visibility or content node with |

data-scope = hello

would lead to all children being evaluated as the scope

data-content = world

would be evaluated as

hello.world

data-content = |world

would be still evaluated as only world if in a scoped branch

food for thought ...

1. Key-Specific Update: If there's a specific key provided (i.e., the key is not undefined), and if the default configuration allows a custom data update for a key, then it triggers a function to update that key with a specific value.

2. General Update: Regardless of the key, if the default configuration allows a custom data update, it triggers a general function to update the key with a specific value.

Here's a rewritten and commented version of the code:

// Check if there's a specific key provided.
if (key !== undefined) {
    // If a key-specific custom data update is allowed, then perform the key-specific update.
    if (getDefault('customDataKeyUpdate')) {
        getDefault('customDataKeyUpdate')(key, value, target, receiver);
    }
}

// If a general custom data update is allowed, then perform the general update.
if (getDefault('customDataUpdate')) {
    getDefault('customDataUpdate')(key, value);
}

Assigning null caused in one case an error with the Symbol Proxy.