text: /* @flow */
  
  import { remove, isDef } from 'shared/util'
  
  export default {
    create (_: any, vnode: VNodeWithData) {
      registerRef(vnode)
    },
    update (oldVnode: VNodeWithData, vnode: VNodeWithData) {
      if (oldVnode.data.ref !== vnode.data.ref) {
        registerRef(oldVnode, true)
        registerRef(vnode)
      }
    },
    destroy (vnode: VNodeWithData) {
      registerRef(vnode, true)
    }
  }
  
  export function registerRef (vnode: VNodeWithData, isRemoval: ?boolean) {
    const key = vnode.data.ref
    if (!isDef(key)) return
  
    const vm = vnode.context
    const ref = vnode.componentInstance || vnode.elm
    const refs = vm.$refs
    if (isRemoval) {
      if (Array.isArray(refs[key])) {
        remove(refs[key], ref)
      } else if (refs[key] === ref) {
        refs[key] = undefined
      }
    } else {
      if (vnode.data.refInFor) {
        if (!Array.isArray(refs[key])) {
          refs[key] = [ref]
        } else if (refs[key].indexOf(ref) < 0) {
          // $flow-disable-line
          refs[key].push(ref)
        }
      } else {
        refs[key] = ref
      }
    }
  }
  