draggable-helper

draggable-helper

A js library to simplify your drag and drop functions. Start with a element, it will expose hooks(drag, moving, drop). You can stop drag, moving and drop by conditions. You can set minTranslate. Its code is easy, you can check source code.

features

• support touch simplify(single touch)
• to prevent page scrolling when touch
• expose hooks(drag, moving, drop)
• prevent drag and moving by return false in hook
• set min translate to trigger drag
• set the style of dragging element
• set the class of dragging element
• move the element or move a cloned one
• check if event is triggered by mouse left button
• to prevent text be selected when dragging
• Advance usage: bind to parent element, make children element as trigger element or moved element. Check example.

install

npm install draggable-helper

usage & api

import draggableHelper from 'draggable-helper'
// dragHandlerEl will be added mouse and touch event listener
const destroy = draggableHelper(HTMLElement dragHandlerEl, Object opt = {})
// opt
// opt will pass to hook, so you can attach custom data into opt, such the data of the element
// startEvent is mousedown or touchstart
opt = {
  // [Object] style, set the style of dragging element
  // getStyle(store, opt), set the style of dragging element
  // [String] draggingClass, default dragging, set the class of dragging element
  // [Boolean] clone, move the element or move a cloned one
  // minTranslate default 10, unit px
  // getEl(dragHandlerEl, store, opt), optional, get the el that will be moved. default is dragHandlerEl
  // afterGetEl(store, opt)
  // [Boolean] triggerBySelf if trigger only by dragHandlerEl self, can not be triggered by children
  // hook, before drag start
  // [Boolean] opt.restoreDOMManuallyOndrop the changed DOM will be restored automatically on drop. This disable it and pass restoreDOM function into store.
  beforeDrag(startEvent, moveEvent, store, opt){
    // when trigger drag, the position must be moved, so there are two event. startEvent also can be accessed by store.startEvent
    // The dragged element at this time has not yet been obtained, store.el is null. 此时要移动的元素还没有获得到, 即store.el是空.
    // return false to prevent drag
  },
  // hook, when drag start
  drag(startEvent, moveEvent, store, opt){
    // when trigger drag, the position must be moved, so there are two event. startEvent also can be accessed by store.startEvent
    // return false to prevent drag
  },
  // hook, when mouse moving
  moving: (moveEvent, store, opt) => {
    // return false to prevent moving
  },
  // hook, when drop
  drop: (endEvent, store, opt) => {
  },
}
// store. life cycle: drag-end
store = {
  el // the moving el
  originalEl // the original moving el, used when clone
  initialMouse
  initialPosition // relative to offsetParent
  mouse
  move
  movedCount // start from 0
  startEvent // mousedown or touchstart event
  endEvent,
  restoreDOM() // function if opt.restoreDOMManuallyOndrop else null
}

Example

Advance usage: bind to parent element

Advance usage: bind to parent element, make children element as trigger element or moved element.

import draggableHelper from 'draggable-helper'
const destroy = draggableHelper(document.body, {
  drag(startEvent, moveEvent, store, opt) {
    // check trigger el
    if (startEvent.target not has class 'your trigger class') {
      return false
    }
  },
  // get the element which will be moved
  getEl: (dragHandlerEl, store, opt) => get the el which will be moved by `store.startEvent.target`
})

prevent drag

In follow case, drag event will be prevented.

• Event target element is follow

const IGNORE_TRIGGERS = ['INPUT','TEXTAREA', 'SELECT', 'OPTGROUP', 'OPTION']

• Event target has class undraggable or its ancestor till dragHandlerEl has.
• opt.beforeDrag or opt.drag return false

demo

jsfiddle