flowtip-react-dom

A FlowTip Component for React DOM

Usage

The FlowTip component works by wrapping some content and positioning it relative to a measured target.

The basic required props are target and Content, with additional optional props providing enhanced behavior.

Any added props that are not used by the FlowTip component are passed down to the Content component when it is rendered. This allows FlowTip to behave as a component "decorator" which enhances the underlying component interface.

Basic Example

This is a minimal example that illustrates using flowtip-react-dom to render a custom tooltip design.`

import React from 'react';
import FlowTip from 'flowtip-react-dom';
import ResizeObserver from 'react-resize-observer';
 
const Content = ({result, children, style}) => (
  <div className="flowtip-content" style={style}>
    {children}
  </div>
);
 
const Tail = ({result, children, style}) => (
  <div className={`flowtip-tail-${result.region}`} style={style}>
    {children}
  </div>
);
 
class FlowTipExample extends React.Component {
  state = {flowTipOpen: false, target: null};
 
  _toggleFlowTip = () => this.setState({flowTipOpen: !this.state.flowTipOpen});
 
  _handleTargetReflow = (target) => this.setState({target});
 
  render() {
    return (
      <div>
        <button onClick={this._toggleFlowTip}>
          <ResizeObserver onReflow={this._handleTargetReflow} />
          Activate FlowTip
        </button>
        {!!this.state.flowTipOpen && (
          <FlowTip target={this.state.target} content={Content} tail={Tail}>
            FlowTip Content
          </FlowTip>
        )}
      </div>
    );
  }
}

Example CSS

.flowtip-content {
  padding: 10px;
  background: white;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.25);
}
 
.flowtip-tail-top,
.flowtip-tail-bottom {
  width: 20px;
  height: 10px;
}
 
.flowtip-tail-right,
.flowtip-tail-left {
  width: 10px;
  height: 20px;
}
 
.flowtip-tail-top::before,
.flowtip-tail-right::before,
.flowtip-tail-bottom::before,
.flowtip-tail-left::before {
  content: '';
  display: block;
}
 
.flowtip-tail-top::before {
  border-left: 10px solid transparent;
  border-right: 10px solid transparent;
  border-top: 10px solid white;
}
 
.flowtip-tail-right::before {
  border-top: 10px solid transparent;
  border-bottom: 10px solid transparent;
  border-right: 10px solid white;
}
 
.flowtip-tail-bottom::before {
  border-left: 10px solid transparent;
  border-right: 10px solid transparent;
  border-bottom: 10px solid white;
}
 
.flowtip-tail-left::before {
  border-top: 10px solid transparent;
  border-bottom: 10px solid transparent;
  border-left: 10px solid white;
}

See Styling FlowTip for more details.

---

Note that the FlowTip component defers all possible state to the parent component.

It does not track the target element position itself and must be provided with an updated target prop any time the target size or position in the viewport changes (react-resize-observer is an excellent tool for this task).

It also does not have any concept of an active or deactivated state, conditionally rendering the entire component is the way to show and hide it.

Styling FlowTip

The FlowTip component renders nothing by itself - deferring all responsibility to the components provided through the tail and content props. This keeps the library as non-opinionated as possible but means that any CSS styles must be manually provided. The only expectation is that the provided style prop be applied to the root content and tail elements.

The style prop contains the calculated CSS position values for the tail and content elements.

When a tail component is provided, FlowTip renders it as a child of the content component, where it is given a absolute position aligning it along the correct edge. FlowTip doesn't attempt to orient the rendered tail element towards the target. Instead, it provides the layout calculation result object as a prop, allowing you to update the styles depending on the current region.

Reference result.region in your tail component to style it in the correct orientation:

const Tail = ({result, children, style}) => (
  <div className={`flowtip-tail-${result.region}`} style={style}>
    {children}
  </div>
);

The result object contains additional information useful for advanced styling tasks. result.offset represents the current distance between the content and the target. result.reason contains a string value (either default, inverted, ideal, external, or fallback) describing the current state of the layout calculation. Checking if the reason value is equal to external is a way to detect if the tail is "detached" from the target - a case where you may want to hide it.

import classNames from 'classnames';
 
const Tail = ({result, children, style}) =>
  <div
    className={classNames(`flowtip-tail-${result.region}`, {
      'flowtip-tail-detached': result.reason === 'external',
    }}
    style={style}
  >
    {children}
  </div>;

.flowtip-tail-detached {
  opacity: 0;
}

Be careful with overly dynamic tail and content styles calculated from the result object. FlowTip can get caught in a feedback loop causing it to rapidly switch between styles. Use opacity to hide your tail element rather than display: none so that its effect on the layout is constant.

It is common to use a "CSS triangle" to render the tail element, due to the way FlowTip measures rendered elements (using react-resize-observer - explained below), retuning a 0px x 0px element with borders will cause layout issues. Make sure that the root tail element represents the total width and height of the tail, with any elements containing borders as children.

This is problematic:

.flowtip-tail-bottom {
  border-left: 10px solid transparent;
  border-right: 10px solid transparent;
  border-bottom: 20px solid white;
}

Problem avoided with nested elements:

.flowtip-tail-bottom .triangle {
  border-left: 10px solid transparent;
  border-right: 10px solid transparent;
  border-bottom: 20px solid white;
}

FlowTip uses react-resize-observer to measure the dimensions of the rendered content and tail elements, which allows it to automatically measure the dimensions of your styled elements. Unfortunately, if the root content element is given a CSS border, the absolutely positioned tail element will be misaligned a distance equal to the width of the border. The solution to this is to apply any necessary border styles to an element that is a child of the content component, leaving it an the tail children of a borderless root element.

Content Border Example:

const Tail = ({result, children, style}) => (
  <div className={`flowtip-tail-${result.region}`} style={style}>
    {children}
  </div>
);
 
const StyledFlowTip = ({children, ...props}) => (
  <FlowTip tail={Tail} {...props}>
    <div className="flowtip-content">{children}</div>
  </FlowTip>
);
 
// Rendering StyledFlowTip component:
{
  !!this.state.flowTipOpen && (
    <StyledFlowTip target={this.state.target}>FlowTip Content</StyledFlowTip>
  );
}

Example CSS

.flowtip-content {
  padding: 10px;
  background: white;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.25);
  border: 2px solid #eee;
}

---

Accessibility & Advanced Behavior

Additional best-practice behaviors like managing user focus or closing the tooltip when the page behind is clicked are not handled by the component itself. We recommend using focus-trap-react to add this functionality.

import React from 'react';
import FlowTip from 'flowtip-react-dom';
import ResizeObserver from 'react-resize-observer';
import FocusTrap from 'focus-trap-react';
 
const Content = ({result, children, style, onClose}) => (
  <FocusTrap
    className="flowtip-content"
    style={style}
    focusTrapOptions={{
      onDeactivate: onClose,
      escapeDeactivates: true,
      clickOutsideDeactivates: true,
    }}
  >
    {children}
  </FocusTrap>
);
 
const Tail = ({result, children, style}) => (
  <div className={`flowtip-tail-${result.region}`} style={style}>
    {children}
  </div>
);
 
class FlowTipExample extends React.Component {
  state = {flowTipOpen: false, target: null};
 
  _openFlowTip = () => this.setState({flowTipOpen: true});
  _closeFlowTip = () => this.setState({flowTipOpen: false});
 
  _handleTargetReflow = (target) => this.setState({target});
 
  render() {
    return (
      <div>
        <button onClick={this._openFlowTip}>
          <ResizeObserver onReflow={this._handleTargetReflow} />
          Activate FlowTip
        </button>
        {!!this.state.flowTipOpen && (
          <FlowTip
            target={this.state.target}
            content={Content}
            tail={Tail}
            onClose={this._closeFlowTip}
          >
            FlowTip Content
          </FlowTip>
        )}
      </div>
    );
  }
}

Component Props

target: object | null

required

The measured position of the target element as a DOMRect-shaped object.

The component will not render any visible content while this prop is null.

bounds: object

optional

The measured position of the available layout area for the tooltip content as a DOMRect-shaped object. This defines the outer collision boundaries referenced by the constrain prop.

If omitted, the viewport rect will be used.

region: string

optional

The preferred region in which the tooltip will appear at first relative to its target. Possibly values are: top, bottom, left, and right.

If region is omitted, the algorithm will pick default to the region with the most available space. (handled by the getIdealRegion function in flowtip-core)

sticky: boolean

optional, default: false

Disabling sticky will make the component reposition its content to occupy whatever the current ideal region is - regardless of its current position.

This results in apparently unnecessary reposition events. When sticky is true, the positioned content will occupy the current region until that region is no longer valid, i.e. the content collides with the boundary edge.

targetOffset: number

optional, default: 0

The desired margin between the positioned content tail and the target.

edgeOffset: number

optional, default: 0

The minimum margin between the positioned content and the boundary. A positive value will prevent the content from touching the boundary edge, a negative value will allow the content to overflow the boundary before a collision is detected.

tailOffset: number

optional, default: 0

The minimum distance between the tail and corner of the content along an edge.

If your content has rounded corners, this should be equal to the radius to prevent the tail from entering the rounded region.

align: string | number

optional, default: center

Linear alignment between the positioned content and the target. Possible values are a number in the range of 0 to 1, or one of start, center, and end (aliases for 0, 0.5, and 1 respectively).

topDisabled: boolean

optional, default: false

Disable rendering the content above the target.

rightDisabled: boolean

optional, default: false

Disable rendering the content to the right of the target.

bottomDisabled: boolean

optional, default: false

Disable rendering the content below the target.

leftDisabled: boolean

optional, default: false

Disable rendering the content to the left of the target.

constrainTop: object

optional, default: true

Disable rendering the content outside the bounds area in the top region.

constrainRight: object

optional, default: true

Disable rendering the content outside the bounds area in the right region.

constrainBottom: object

optional, default: true

Disable rendering the content outside the bounds area in the bottom region.

constrainLeft: object

optional, default: true

Disable rendering the content outside the bounds area in the left region.

Content: ReactClass<{style: Object, result: Result}>,

content: function | string

optional, default: div

A React Class or stateless component responsible for rendering the tooltip content.

FlowTip renders this component with children, style, and result props. The children and style props must be passed to its root HTML tag element for content positioning to work.

Example Content component:

const Content = ({result, children, style}) =>
  <div className='flowtip-content' style={style} >
    {children}
    Current region: {result.region}
  </div>;
...
 
<FlowTip Content={Content} ... />

FlowTip will default to rendering an unstyled div element if the content prop is omitted. Content styling can be handled by child element in this case.

tail: function

optional

An optional React Class or stateless component responsible for rendering the tail content.

FlowTip renders this component with children, style, and result props. The children and style props must be passed to its root HTML tag element for tail positioning to work.

Example Tail component:

const Tail = ({result, children, style}) =>
  <div className={`flowtip-tail-${result.region}`} style={style} >
    {children}
  </div>;
...
 
<FlowTip Tail={Tail} ... />

Rect Interface

While flowtip-core has no dependency on the DOM, it is designed to be directly compatible with DOMRect instances returned from getClientBoundingRect() calls. Any object that satisfies the DOMRect object interface top: number, left: number, width: number, height: number, bottom?: number, right?: number can be used.

The absolute reference frame of the measurements does not have an impact on the calculation - as long as all measurements are relative to the same frame.