leave() — vue Function Reference

Source Code

src/platforms/web/runtime/modules/transition.ts lines 169–275

export function leave(vnode: VNodeWithData, rm: Function) {
  const el: any = vnode.elm

  // call enter callback now
  if (isDef(el._enterCb)) {
    el._enterCb.cancelled = true
    el._enterCb()
  }

  const data = resolveTransition(vnode.data.transition)
  if (isUndef(data) || el.nodeType !== 1) {
    return rm()
  }

  /* istanbul ignore if */
  if (isDef(el._leaveCb)) {
    return
  }

  const {
    css,
    type,
    leaveClass,
    leaveToClass,
    leaveActiveClass,
    beforeLeave,
    leave,
    afterLeave,
    leaveCancelled,
    delayLeave,
    duration
  } = data

  const expectsCSS = css !== false && !isIE9
  const userWantsControl = getHookArgumentsLength(leave)

  const explicitLeaveDuration: any = toNumber(
    isObject(duration) ? duration.leave : duration
  )

  if (__DEV__ && isDef(explicitLeaveDuration)) {
    checkDuration(explicitLeaveDuration, 'leave', vnode)
  }

  const cb = (el._leaveCb = once(() => {
    if (el.parentNode && el.parentNode._pending) {
      el.parentNode._pending[vnode.key!] = null
    }
    if (expectsCSS) {
      removeTransitionClass(el, leaveToClass)
      removeTransitionClass(el, leaveActiveClass)
    }
    // @ts-expect-error
    if (cb.cancelled) {
      if (expectsCSS) {
        removeTransitionClass(el, leaveClass)
      }
      leaveCancelled && leaveCancelled(el)
    } else {
      rm()
      afterLeave && afterLeave(el)
    }
    el._leaveCb = null
  }))

  if (delayLeave) {
    delayLeave(performLeave)
  } else {
    performLeave()
  }

  function performLeave() {
    // the delayed leave may have already been cancelled
    // @ts-expect-error
    if (cb.cancelled) {
      return
    }
    // record leaving element
    if (!vnode.data.show && el.parentNode) {
      ;(el.parentNode._pending || (el.parentNode._pending = {}))[vnode.key!] =
        vnode
    }
    beforeLeave && beforeLeave(el)
    if (expectsCSS) {
      addTransitionClass(el, leaveClass)
      addTransitionClass(el, leaveActiveClass)
      nextFrame(() => {
        removeTransitionClass(el, leaveClass)
        // @ts-expect-error
        if (!cb.cancelled) {
          addTransitionClass(el, leaveToClass)
          if (!userWantsControl) {
            if (isValidDuration(explicitLeaveDuration)) {
              setTimeout(cb, explicitLeaveDuration)
            } else {
              whenTransitionEnds(el, type, cb)
            }
          }
        }
      })
    }
    leave && leave(el, cb)
    if (!expectsCSS && !userWantsControl) {
      cb()
    }
  }
}