diff --git a/src/GeoTimeScale.ts b/src/GeoTimeScale.ts
index faf29d9..4acd261 100644
--- a/src/GeoTimeScale.ts
+++ b/src/GeoTimeScale.ts
@@ -351,6 +351,9 @@ export default class GeoTimeLine {
             .attr("opacity", (d) =>
               d.visible ? 1 : 0
             )
+            .attr("display", (d) =>
+              d.visible ? 'block' : 'none'
+            )
             .attr("transform", (d) => `translate(${d.targetX}, ${d.y})`)
             .attr("dominant-baseline", "hanging")
             .attr("text-anchor", (d) =>
diff --git a/src/typing.ts b/src/typing.ts
index 71d0d25..dd0996c 100644
--- a/src/typing.ts
+++ b/src/typing.ts
@@ -1,4 +1,4 @@
-import { HierarchyRectangularNode, ZoomTransform } from "d3";
+import { ZoomTransform } from "d3";
 
 /** geo time data intervals schema **/
 export type IntervalItem = {
@@ -103,4 +103,193 @@ export type d3ZoomEvent = {
   sourceEvent: WheelEvent | MouseEvent,
   target: any;
   transform: ZoomTransform;
+}
+
+// copy from d3
+export interface HierarchyLink<Datum> {
+  /**
+   * The source of the link.
+   */
+  source: HierarchyNode<Datum>;
+
+  /**
+   * The target of the link.
+   */
+  target: HierarchyNode<Datum>;
+}
+
+export interface HierarchyNode<Datum> {
+  /**
+   * The associated data, as specified to the constructor.
+   */
+  data: Datum;
+
+  /**
+   * Zero for the root node, and increasing by one for each descendant generation.
+   */
+  readonly depth: number;
+
+  /**
+   * Zero for leaf nodes, and the greatest distance from any descendant leaf for internal nodes.
+   */
+  readonly height: number;
+
+  /**
+   * The parent node, or null for the root node.
+   */
+  parent: this | null;
+
+  /**
+   * An array of child nodes, if any; undefined for leaf nodes.
+   */
+  children?: this[] | undefined;
+
+  /**
+   * Aggregated numeric value as calculated by `sum(value)` or `count()`, if previously invoked.
+   */
+  readonly value?: number | undefined;
+
+  /**
+   * Optional node id string set by `StratifyOperator`, if hierarchical data was created from tabular data using stratify().
+   */
+  readonly id?: string | undefined;
+
+  /**
+   * Returns the array of ancestors nodes, starting with this node, then followed by each parent up to the root.
+   */
+  ancestors(): this[];
+
+  /**
+   * Returns the array of descendant nodes, starting with this node, then followed by each child in topological order.
+   */
+  descendants(): this[];
+
+  /**
+   * Returns the array of leaf nodes in traversal order; leaves are nodes with no children.
+   */
+  leaves(): this[];
+
+  /**
+   * Returns the first node in the hierarchy from this node for which the specified filter returns a truthy value. undefined if no such node is found.
+   * @param filter Filter.
+   */
+  find(filter: (node: this) => boolean): this | undefined;
+
+  /**
+   * Returns the shortest path through the hierarchy from this node to the specified target node.
+   * The path starts at this node, ascends to the least common ancestor of this node and the target node, and then descends to the target node.
+   *
+   * @param target The target node.
+   */
+  path(target: this): this[];
+
+  /**
+   * Returns an array of links for this node, where each link is an object that defines source and target properties.
+   * The source of each link is the parent node, and the target is a child node.
+   */
+  links(): Array<HierarchyLink<Datum>>;
+
+  /**
+   * Evaluates the specified value function for this node and each descendant in post-order traversal, and returns this node.
+   * The `node.value` property of each node is set to the numeric value returned by the specified function plus the combined value of all descendants.
+   *
+   * @param value The value function is passed the node’s data, and must return a non-negative number.
+   */
+  sum(value: (d: Datum) => number): this;
+
+  /**
+   * Computes the number of leaves under this node and assigns it to `node.value`, and similarly for every descendant of node.
+   * If this node is a leaf, its count is one. Returns this node.
+   */
+  count(): this;
+
+  /**
+   * Sorts the children of this node, if any, and each of this node’s descendants’ children,
+   * in pre-order traversal using the specified compare function, and returns this node.
+   *
+   * @param compare The compare function is passed two nodes a and b to compare.
+   * If a should be before b, the function must return a value less than zero;
+   * if b should be before a, the function must return a value greater than zero;
+   * otherwise, the relative order of a and b are not specified. See `array.sort` for more.
+   */
+  sort(compare: (a: this, b: this) => number): this;
+
+  /**
+   * Returns an iterator over the node’s descendants in breadth-first order.
+   */
+  [Symbol.iterator](): Iterator<this>;
+
+  /**
+   * Invokes the specified function for node and each descendant in breadth-first order,
+   * such that a given node is only visited if all nodes of lesser depth have already been visited,
+   * as well as all preceding nodes of the same depth.
+   *
+   * @param func The specified function is passed the current descendant, the zero-based traversal index, and this node.
+   * @param that If that is specified, it is the this context of the callback.
+   */
+  each<T = undefined>(func: (this: T, node: this, index: number, thisNode: this) => void, that?: T): this;
+
+  /**
+   * Invokes the specified function for node and each descendant in post-order traversal,
+   * such that a given node is only visited after all of its descendants have already been visited.
+   *
+   * @param func The specified function is passed the current descendant, the zero-based traversal index, and this node.
+   * @param that If that is specified, it is the this context of the callback.
+   *
+   */
+  eachAfter<T = undefined>(func: (this: T, node: this, index: number, thisNode: this) => void, that?: T): this;
+
+  /**
+   * Invokes the specified function for node and each descendant in pre-order traversal,
+   * such that a given node is only visited after all of its ancestors have already been visited.
+   *
+   * @param func The specified function is passed the current descendant, the zero-based traversal index, and this node.
+   * @param that If that is specified, it is the this context of the callback.
+   */
+  eachBefore<T = undefined>(func: (this: T, node: this, index: number, thisNode: this) => void, that?: T): this;
+
+  /**
+   * Return a deep copy of the subtree starting at this node. The returned deep copy shares the same data, however.
+   * The returned node is the root of a new tree; the returned node’s parent is always null and its depth is always zero.
+   */
+  copy(): this;
+}
+
+export interface HierarchyRectangularLink<Datum> {
+  /**
+   * The source of the link.
+   */
+  source: HierarchyRectangularNode<Datum>;
+
+  /**
+   * The target of the link.
+   */
+  target: HierarchyRectangularNode<Datum>;
+}
+export interface HierarchyRectangularNode<Datum> extends HierarchyNode<Datum> {
+  /**
+   * The left edge of the rectangle.
+   */
+  x0: number;
+
+  /**
+   * The top edge of the rectangle
+   */
+  y0: number;
+
+  /**
+   * The right edge of the rectangle.
+   */
+  x1: number;
+
+  /**
+   * The bottom edge of the rectangle.
+   */
+  y1: number;
+
+  /**
+   * Returns an array of links for this node, where each link is an object that defines source and target properties.
+   * The source of each link is the parent node, and the target is a child node.
+   */
+  links(): Array<HierarchyRectangularLink<Datum>>;
 }
\ No newline at end of file