@vx/tooltip

The @vx/tooltip package provides utilities for making it easy to add Tooltips to a visualization and includes hooks, higher-order component (HOC) enhancers, and Tooltip components.

Installation

npm install --save @vx/tooltip

Hooks and Enhancers

This package provides two ways to add tooltip state logic to your chart components:

• a hook: useTooltip()
• a higher order component (HOC): withTooltip()

The useTooltip hook is the recommended way to add tooltip state logic to your components, but can only be used in functional components. The withTooltip HOC can be used with both functional and class components, and is the recommended way to add tooltip state logic to class components.

Both useTooltip and withTooltip expose the same values and functions for use in your component:

In the case of useTooltip, these will be returned from the useTooltip() call in your component. In the case of withTooltip, they will be passed as props to your wrapped component. Refer to the Examples section for a basic demo of each approach.

useTooltip()

If you would like to add tooltip state logic to a functional component, you may use the useTooltip() hook which will return an object with several properties that you can use to manage the tooltip state of your component. For correct tooltip positioning, it is important to wrap your component in an element (e.g., div) with relative positioning. This is handled for you by the withTooltip HOC, but not with the useTooltip() hook.

withTooltip(BaseComponent [, containerProps , renderContainer])

If you would like to add tooltip state logic to a class component, you may wrap it in withTooltip(BaseComponent [, containerProps [, renderContainer]).

The HOC will wrap your component in a div with relative positioning by default and handle state for tooltip positioning, visibility, and content by injecting the following props into your BaseComponent:

You may override the container by specifying containerProps as the second argument to withTooltip, or by specifying renderContainer as the third argument to withTooltip.

Components

Tooltip components render tooltip state and can be used in conjunction with useTooltip and withTooltip above.

Tooltip

This is a simple Tooltip container component meant to be used to actually render a Tooltip. It accepts the following props, and will spread any additional props on the tooltip container div (i.e., ...restProps):

TooltipWithBounds

This tooltip component is exactly the same as Tooltip above, but it is aware of its boundaries meaning that it will flip left/right and bottom/top based on whether it would overflow its parent's boundaries. It accepts the following props, and will spread any additional props on the Tooltip component (i.e., ...restProps):

Note that this component is positioned using a transform, so overriding left and top via styles may have no effect.

useTooltipInPortal

⚠️ ResizeObserver dependency

This hook relies on ResizeObservers. If you need a polyfill, you can either polute the window object or inject it cleanly using the polyfill config option below.

useTooltipInPortal is a hook which gives you a TooltipInPortal component for rendering Tooltip or TooltipWithBounds in a Portal, outside of your component DOM tree which can be useful in many circumstances (see below for more on Portals).

API

type Options = {
  /** whether TooltipWithBounds should be used to auto-detect (page) boundaries and reposition itself. */
  detectBounds?: boolean;
  /** Debounce resize or scroll events in milliseconds (needed for positioning) **/
  debounce?: number | { scroll: number; resize: number }
  /** React to nested scroll changes, don't use this if you know your view is static */
  scroll?: boolean
  /** You can optionally inject a resize-observer polyfill */
  polyfill?: { new (cb: ResizeObserverCallback): ResizeObserver }
}

useTooltipInPortal(
  options: Options = { debounce: 0, scroll: true, detectBounds: true }
): {
  /** Set `ref={containerRef}` on the element corresponding to the coordinate system that `left/top` (passed to `TooltipInPortal`) are relative to. */
  containerRef: React.MutableRefObject<HTMLElement | SVGElement>;
  /** Access to the container's bounding box if useful to you. This will be empty on first render. */
  containterBounds: RectReadOnly;
  /** React.FunctionComponent<TooltipProps> with the same API as Tooltip, which will be rendered in a Portal. */
  TooltipInPortal ({ top: containerTop, left: containerLeft, ...tooltipProps }: TooltipProps) => ReactNode;


interface RectReadOnly {
  readonly x: number
  readonly y: number
  readonly width: number
  readonly height: number
  readonly top: number
  readonly right: number
  readonly bottom: number
  readonly left: number
}

Portal

Portal is a component which simply renders its children inside a div element appended to document.body created by ReactDOM. A Portal can be an effective strategy for solving the (z-index stacking context problem)rg/en-US/docs/Web/CSS/CSS_Positioning/Understanding_z_index/The_stacking_context for Tooltips.

For example, if your chart is rendered inside a stacking context with a lower z-index than a surrounding container, it may get clipped by that container even if you specify a higher z-index. This is solvable with a Portal because the separate container will not be subject to the stacking context of your chart.

To use a Portal, simply pass your Tooltip as a child: <Portal><Tooltip {...} /></Portal>. You will also need to correct the left and top positions to be in page coordinates, not the coordinates of your container which you would use when not using a Portal. If reacting to a mouse event, you can use event.pageX/Y. Alternatively, if you have container coordinates, you can convert them to page coordinates using the following (note: useTooltipInPortal does handles this for you):

const pageX = containerX + containerBoundingBox.left + window.scrollLeft;
const pageY = containerY + containerBoundingBox.top + window.scrollTop;

Examples

useTooltip and useTooltipInPortal For Functional Components

import { useTooltip, useTooltipInPortal, TooltipWithBounds } from '@vx/tooltip';
import { localPoint } from '@vx/event';

const ChartWithTooltip = () => {
  const {
    tooltipData,
    tooltipLeft,
    tooltipTop,
    tooltipOpen,
    showTooltip,
    hideTooltip,
  } = useTooltip();

  // If you don't want to use a Portal, simply replace `TooltipInPortal` below with
  // `Tooltip` or `TooltipWithBounds` and remove `containerRef`
  const { containerRef, TooltipInPortal } = useTooltipInPortal({
    // use TooltipWithBounds
    detectBounds: true,
    // when tooltip containers are scrolled, this will correctly update the Tooltip position
    scroll: true,
  })

  const handleMouseOver = (event, datum) => {
    const coords = localPoint(event.target.ownerSVGElement, event);
    showTooltip({
      tooltipLeft: coords.x,
      tooltipTop: coords.y,
      tooltipData: datum
    });
  };

  return (
    // Set `ref={containerRef}` on the element corresponding to the coordinate system that
    // `left/top` (passed to `TooltipInPortal`) are relative to.
    <>
      <svg ref={containerRef} width={...} height={...}>
        // Chart here...
        <SomeChartElement
          onMouseOver={this.handleMouseOver}
          onMouseOut={hideTooltip}
        />
      </svg>

      {tooltipOpen && (
        <TooltipInPortal
          // set this to random so it correctly updates with parent bounds
          key={Math.random()}
          top={tooltipTop}
          left={tooltipLeft}
        >
          Data value <strong>{tooltipData}</strong>
        </TooltipInPortal>
      )}
    </>
  )
};

render(<ChartWithTooltip />, document.getElementById("root"));

withTooltip For Class Components

import { withTooltip, TooltipWithBounds } from '@vx/tooltip';
import { localPoint } from '@vx/event';

class Chart extends React.Component {
  handleMouseOver = (event, datum) => {
    const coords = localPoint(event.target.ownerSVGElement, event);
    this.props.showTooltip({
      tooltipLeft: coords.x,
      tooltipTop: coords.y,
      tooltipData: datum
    });
  };

  render() {
    const {
      tooltipData,
      tooltipLeft,
      tooltipTop,
      tooltipOpen,
      hideTooltip
    } = this.props;

    return (
      // note React.Fragment is only available in >= react@16.2
      <React.Fragment>
        <svg width={...} height={...}>
          // Chart here...
          <SomeChartElement onMouseOver={this.handleMouseOver} onMouseOut={hideTooltip} />
        </svg>

        {tooltipOpen && (
          <TooltipWithBounds
            // set this to random so it correctly updates with parent bounds
            key={Math.random()}
            top={tooltipTop}
            left={tooltipLeft}
          >
            Data value <strong>{tooltipData}</strong>
          </TooltipWithBounds>
        )}
      </React.Fragment>
    );
  }
}

const ChartWithTooltip = withTooltip(Chart);

render(<ChartWithTooltip />, document.getElementById("root"));

Example codesandbox here.