nanodrag

A small library to simplify the handling of drag events on mouse & touch devices.

Usage

const Nanodrag = require('nanodrag')
const div = document.createElement('div')
const nd = Nanodrag(div)

nd.on('start', (data) => {
  console.log('Drag started!', data)
})

nd.on('move', (data) => {
  console.log('Dragging!', data)
})

nd.on('end', (data) => {
  console.log('Drag finished!', data)
})

nd.close()

API

Properties

preventDefault:boolean

If this is set to true, it will call event.preventDefault() on the event provided by the touchmove or mousemove event. This property only works if you did not set {passive: true} in the constructor.

Examples:

This will attach the listener in passive mode and prevent the calling of event.preventDefault regardless of what value Nanodrag.preventDefault is.

const nd = new Nanodrag(element, {passive: true})

This will attach the listener in active mode allowing you decide to call event.preventDefault at a later time.

const nd = new Nanodrag(element)
nd.on('start', () => {
  nd.preventDefault = false
})

Methods

new Nanodrag(selector:string|element:HTMLElement, options?:object(key:any)):nanodrag

Create a new nanodrag instance. You can either pass in a valid selector for .querySelector or a reference to an HTML element. A nanodrag instance is also an instance of a nanobus object.

options

• trackingDelay?:number - the delay (in nanoseconds) to wait before turning off the tracking mode if the mouse escapes the tracked element. Default: 300
• passive?:boolean - attach touchmove and mousemove as passive listeners. This will prevent calling event.preventDefault on move events.

nanodrag#on(event:string, listener:function)

Provide a function to invoke when the specified event is triggered

nanodrag#once(event:string, listener:function)

Attach an event to invoke only once

nanodrag#emit(event:string, data:any)

Invoke an event with a specific payload of data

nanodrag#removeListener(event:string, listener:function)

Remove a specific listener

nanodrag#removeAllListeners(event?:string)

Remove all listeners for a given event; if no event is specified, removed all listeners.

nanodrag#close()

Remove all listeners on the DOM as well as on the nanobus instances and stop reporting any move events

Events

start

Triggered when a touch start or mouse down event occur on the nanodrag element.

data

• start:object
  • x:number - the x coordinate of the touch instrument or mouse
  • y:number - the y coordinate of the touch instrument or mouse

move

Triggered when the mouse or touch instrument is moved after being started. For mouse-like devices, this means the button must be actively held down

data

• start:object
  • x:number - the starting x coordinate of the touch instrument or mouse
  • y:number - the starting y coordinate of the touch instrument or mouse
• current:object
  • x:number - the current x coordinate of the touch instrument or mouse
  • y:number - the current y coordinate of the touch instrument or mouse
• direction:object
  • x:string - either 'left' or 'right
  • y:string - either 'up' or 'down

end

Triggered when the touchend or mouseup event occurs.

data

• start:object
  • x:number - the starting x coordinate of the touch instrument or mouse
  • y:number - the starting y coordinate of the touch instrument or mouse
• end:object
  • x:number - the end x coordinate of the touch instrument or mouse
  • y:number - the end y coordinate of the touch instrument or mouse

License

Copyright © 2018 Todd Kennedy, Apache 2.0 License