Function flattenTree

flattenTree<T>(
    data: T | readonly T[],
    getKey: (node: T) => string,
    getChildren: ((node: T) => readonly T[] | undefined) | undefined,
    hasChildrenFn: ((node: T) => boolean) | undefined,
    expanded: readonly string[],
    expandedSet?: ReadonlySet<string>,
): readonly Readonly<
    {
        ancestorIsLast: readonly boolean[];
        depth: number;
        hasChildren: boolean;
        key: string;
        node: T;
        parentKey: string
        | null;
        siblingCount: number;
        siblingIndex: number;
    },
>[]
Flatten a tree into a list of visible nodes.

Only includes nodes whose ancestors are all expanded. Order is depth-first pre-order traversal.
Type Parameters
- T
Parameters
- data: T | readonly T[]
  Root node(s)
- getKey: (node: T) => string
  Function to get node key
- getChildren: ((node: T) => readonly T[] | undefined) | undefined
  Function to get node children
- hasChildrenFn: ((node: T) => boolean) | undefined
  Function to check if node has children
- expanded: readonly string[]
  Set of expanded node keys
- OptionalexpandedSet: ReadonlySet<string>
Returns readonly Readonly<
    {
        ancestorIsLast: readonly boolean[];
        depth: number;
        hasChildren: boolean;
        key: string;
        node: T;
        parentKey: string
        | null;
        siblingCount: number;
        siblingIndex: number;
    },
>[]
Array of flattened nodes
- Defined in core/src/widgets/tree.ts:55