Document 3 — Adding Another Node Structural Growth

The previous example had two root nodes: customer and order. Now we add a third root node: product.

Nothing in the traversal code changes. We only change the source structure and describe the new node with an instruction.

1. The Original Source

{
  "customer": {
    "name": "Keshav"
  },
  "order": {
    "id": "ORD-101"
  }
}

2. Add One More Root Node

{
  "customer": {
    "name": "Keshav"
  },
  "order": {
    "id": "ORD-101"
  },
  "product": {
    "code": "P-100"
  }
}

We have simply added product. The traversal engine does not need to know in advance that this node was added.

3. Add Its Instruction

{
  "customer": {
    "transform": "logPath"
  },
  "order": {
    "transform": "logPath"
  },
  "product": {
    "transform": "logPath"
  }
}

Now when traversal reaches product, it finds its instruction, understands it, and continues the exact same process.

4. The Same External Function

function logPath(value, path) {
  console.log("I am here in the tree:", path, value);
}

We did not create a new function for product. The same external function is reused.

5. Runtime Result

I am here in the tree: customer.name Keshav
I am here in the tree: order.id ORD-101
I am here in the tree: product.code P-100

The Point

Adding a node does not require changing the traversal algorithm. The source describes the structure and the instructions describe what should happen at that structure.