quasar/src/utils/event.js

Build high-performance VueJS user interfaces (SPA, PWA, SSR, Mobile and Desktop) in record time

export const listenOpts = {
  hasPassive: false,
  passiveCapture: true,
  notPassiveCapture: true
}

try {
  var opts = Object.defineProperty({}, 'passive', {
    get () {
      Object.assign(listenOpts, {
        hasPassive: true,
        passive: { passive: true },
        notPassive: { passive: false },
        passiveCapture: { passive: true, capture: true },
        notPassiveCapture: { passive: false, capture: true }
      })
    }
  })
  window.addEventListener('qtest', null, opts)
  window.removeEventListener('qtest', null, opts)
}
catch (e) {}

export function noop () {}

export function leftClick (e) {
  return e.button === 0
}

export function middleClick (e) {
  return e.button === 1
}

export function rightClick (e) {
  return e.button === 2
}

export function position (e) {
  if (e.touches && e.touches[0]) {
    e = e.touches[0]
  }
  else if (e.changedTouches && e.changedTouches[0]) {
    e = e.changedTouches[0]
  }
  else if (e.targetTouches && e.targetTouches[0]) {
    e = e.targetTouches[0]
  }

  return {
    top: e.clientY,
    left: e.clientX
  }
}

export function getEventPath (e) {
  if (e.path) {
    return e.path
  }
  if (e.composedPath) {
    return e.composedPath()
  }

  const path = []
  let el = e.target

  while (el) {
    path.push(el)

    if (el.tagName === 'HTML') {
      path.push(document)
      path.push(window)
      return path
    }

    el = el.parentElement
  }
}

// Reasonable defaults
const
  LINE_HEIGHT = 40,
  PAGE_HEIGHT = 800

export function getMouseWheelDistance (e) {
  let x = e.deltaX, y = e.deltaY

  if ((x || y) && e.deltaMode) {
    const multiplier = e.deltaMode === 1 ? LINE_HEIGHT : PAGE_HEIGHT
    x *= multiplier
    y *= multiplier
  }

  if (e.shiftKey && !x) {
    [y, x] = [x, y]
  }

  return { x, y }
}

export function stop (e) {
  e.stopPropagation()
}

export function prevent (e) {
  e.cancelable !== false && e.preventDefault()
}

export function stopAndPrevent (e) {
  e.cancelable !== false && e.preventDefault()
  e.stopPropagation()
}

export function stopAndPreventClick (evt) {
  stopAndPrevent(evt)

  if (evt.type === 'mousedown') {
    const handler = e => {
      e.target === evt.target && stopAndPrevent(e)
      document.removeEventListener('click', handler, listenOpts.notPassiveCapture)
    }

    document.addEventListener('click', handler, listenOpts.notPassiveCapture)
  }
}

export function preventDraggable (el, status) {
  if (el === void 0 || (status === true && el.__dragPrevented === true)) {
    return
  }

  const fn = status === true
    ? el => {
      el.__dragPrevented = true
      el.addEventListener('dragstart', prevent, listenOpts.notPassiveCapture)
    }
    : el => {
      delete el.__dragPrevented
      el.removeEventListener('dragstart', prevent, listenOpts.notPassiveCapture)
    }

  el.querySelectorAll('a, img').forEach(fn)
}

export function create (name, { bubbles = false, cancelable = false } = {}) {
  try {
    return new CustomEvent(name, { bubbles, cancelable })
  }
  catch (e) {
    // IE doesn't support `new Event()`, so...
    const evt = document.createEvent('Event')
    evt.initEvent(name, bubbles, cancelable)
    return evt
  }
}

export function addEvt (ctx, targetName, events) {
  const name = `__q_${targetName}_evt`

  ctx[name] = ctx[name] !== void 0
    ? ctx[name].concat(events)
    : events

  events.forEach(evt => {
    evt[0].addEventListener(evt[1], ctx[evt[2]], listenOpts[evt[3]])
  })
}

export function cleanEvt (ctx, targetName) {
  const name = `__q_${targetName}_evt`

  if (ctx[name] !== void 0) {
    ctx[name].forEach(evt => {
      evt[0].removeEventListener(evt[1], ctx[evt[2]], listenOpts[evt[3]])
    })
    ctx[name] = void 0
  }
}

/*
 * also update /types/utils/event.d.ts
 */

export default {
  listenOpts,
  leftClick,
  middleClick,
  rightClick,
  position,
  getEventPath,
  getMouseWheelDistance,
  stop,
  prevent,
  stopAndPrevent,
  preventDraggable,
  create
}