Stratify Transform
The stratify transform generates a hierarchical (tree) data structure from input data objects, based on key fields that match parent and children nodes. Internally, this transform generates a set of tree node objects that can then be processed by tree layout methods such as tree, treemap, pack, and partition.
Transform Parameters
| Property | Type | Description |
|---|---|---|
| key | Field | Required. A data field containing a unique key (identifier) for each node. |
| parentKey | Field | Required. A data field containing the key value for each node’s parent in the hierarchy. To indicate the root node of the tree, the parentKey value must be one of null, undefined, or the empty string ''. |
Usage
{
"type": "stratify",
"key": "id",
"parentKey": "parent"
}
Builds a tree data structure from input data objects, such that each node (identified by key) is made the child of a parent node according to the child’s parentKey field.
For example, given this input data:
[
{"id": "A", "parent": null},
{"id": "B", "parent": "A"},
{"id": "C", "parent": "A"},
{"id": "D", "parent": "C"},
{"id": "E", "parent": "C"}
]
The resulting tree structure is:
/- B
A
\- C - [D, E]