vue typescript element

submitForm (formName) {
  this.$refs[formName].validate((valid) => {
    if (valid) {
      alert('submit!')
    } else {
      console.log('error submit!!')
      return false
    }
  })

TS2339: Property 'validate' does not exist on type 'Vue | Element | Vue[] | Element[]'.
Property 'validate' does not exist on type 'Vue'.

submitForm (formName) {
  let el:any = this.$refs[formName]
  el.validate((valid) => {
    if (valid) {
      alert('submit!')
    } else {
      console.log('error submit!!')
      return false
    }
  })
}