wp-calypso/client/lib/hover-intent/README.md

Hoverintent

HoverIntent is a wrapper component that attempts to determine the user's intent of hovering over the child element in which case returns the onMouseOver event or onMouseOut if onMouseOver was previously triggered. The most common scenarios:

1. Having a button that triggers a popover (example below). In that case, when user hovers their mouse fast over the element but doesn't stop over the element then onMouseOver will not be triggered.

2. Evaluating the users intention to move the cursor to a flyout submenu.

Props

onMouseOver : The callback to fire on mouse over event

onMouseOut : The callback to fire on mouse out event

timeout : A simple delay, in milliseconds, before the onMouseOut callback is fired. If the user mouses back over the element before the timeout has expired the onMouseOut callback will not be called (nor will the onMouseOver callback be called). This is primarily to protect against sloppy/human mousing trajectories that temporarily (and unintentionally) take the user off of the target element... giving them time to return.

Default timeout: 0

sensitivity : If the mouse travels fewer than this number of pixels between polling intervals, then the onMouseOver callback will be called. With the minimum sensitivity threshold of 1, the mouse must not move between polling intervals. With higher sensitivity thresholds you are more likely to receive a false positive.

Default sensitivity: 7

interval : The number of milliseconds hoverIntent waits between reading/comparing mouse coordinates. When the user's mouse first enters the element its coordinates are recorded. The soonest the onMouseOut callback can be called is after a single polling interval. Setting the polling interval higher will increase the delay before the first possible onMouseOver call, but also increases the time to the next point of comparison.

Default interval: 700

Example

import clsx from 'clsx';
import HoverIntent from 'calypso/lib/hover-intent';

class App extends Component {
    constructor() {
        super();
        this.state = { mouseover: false };
    }
    onMouseOver = () => {
        this.setState( { mouseover: true } );
    };
    onMouseOut = () => {
        this.setState( { mouseover: false } );
    };
    render() {
        const { mouseover } = this.state;
        return (
            <div className="container">
                <HoverIntent
                    onMouseOver={ this.onMouseOver }
                    onMouseOut={ this.onMouseOut }
                    sensitivity={ 10 }
                    interval={ 1000 }
                    timeout={ 250 }
                >
                    <button>Hover</button>
                </HoverIntent>
                <span className={ clsx( 'popover', { open: mouseover } ) }>Hover</span>
            </div>
        );
    }
}