原因：默认源码中关于指令的el声明的是HTMLElement类型，但是该类型是没有disabled属性的。

解决如下：

// db-click.ts
import { DirectiveOptions } from 'vue'
// To prevent the double click on the button, you can use this directive like: v-dbClick.
interface HTMLElementPlus extends HTMLElement {
  disabled?: boolean
}
export const dbClick: DirectiveOptions = {
  bind(el: HTMLElementPlus) {
    el.addEventListener('click', e => {
      console.log(e)
      if (!el.disabled) {
        el.disabled = true
        el.style.cursor = 'not-allowed'
        setTimeout(() => {
          el.style.cursor = 'pointer'
          el.disabled = false
        }, 1500)  // 1500毫秒
      }
    })
  }
}