vue 输入一个小数点 vue指令只能输入正数并且只能输入一个小数点的方法

Vue.directive('numbers', {
 bind: function (el, binding) {
  console.log('ere')
 },
 inserted: function (el) {
  // el.querySelector('input').blur(console.log('etset'))
 },
 update: function (el, binding, vnode, oldVnode) {
  console.log('vnode', vnode)
  let express = vnode.data.directives[1].expression
  // let value = el.querySelector('input').value
  let value = vnode.data.directives[1].value
  if (typeof value === 'string') {} //在重置的时候清空
  if (value.split('.').length - 1 > 1) {
   value = value.replace(/\.{2,}/g, '') // 只保留第一个. 清除多余的
   value = value.replace('.', '$#$').replace(/\./g, '').replace('$#$', '.')
  }
  let repeatValue = value.replace(/[^\d.]/g, '')
  // setTimeout(() => {
  //  el.querySelector('input').value = repeatValue
  // }, 5)
  setValueWithExpressionVue(vnode.context.$data, express, repeatValue)
 },
 componentUpdated: function () {},
 unbind: function (el) {}
})

// 
function setValueWithExpressionVue (currObj, expression, value) {
 expression = expression.split('.')
 expression.forEach(function (arg, i) {
  if (i < expression.length - 1) {
   currObj = currObj[arg]
  } else {
   currObj[arg] = value
  }
 })
}