fold

fold is a DTL operation that collapses a single-child mapping by promoting its only child.

Use it to remove unnecessary wrapper nodes.

YOp

- fold:
    path: config/wrapper

Parameters

Parameter	Type	Required	Description
path	string	yes	Path to the wrapper mapping. It must have exactly one child key.

Behavior

• Requires the path to exist.
• Requires the target to be a mapping with exactly one key.
• Removes the wrapper key.
• Promotes the single child to the wrapper's former position.

Errors

Error	Meaning
PATH_NOT_FOUND	Target path does not exist.
NOT_FOLDABLE	The mapping has zero keys or more than one key.

Example

yops:
  - fold:
      path: config/wrapper

Input:

config:
  wrapper:
    actual:
      data: 1

Output:

config:
  actual:
    data: 1