vue自定义长按指令

//长按指令
export default {
    install(Vue, options = {
      time: 2000
    }) {
      Vue.directive('longpress', {
        bind: function(el, binding, vNode) {
          // 确保提供的表达式是函数
          if (typeof binding.value !== 'function') {
            // 获取组件名称
            const compName = vNode.context.name;
            // 将警告传递给控制台
            let warn = `[longpress:] provided expression '${binding.expression}' is not afunction, but has to be `;
            if (compName) { warn += `Found in component '${compName}' `}
            console.warn(warn);
          }
          // 定义变量
          let pressTimer = null;
          // 定义函数处理程序
          // 建立计时器（ 1秒后执行函数 ）
          let start = (e) => {
            if (e.type === 'click' && e.button !== 0) {
              return;
            }
            if (pressTimer === null) {
              pressTimer = setTimeout(() => {
                // 执行函数
                handler(e);
              }, options.time)
            }
          }
          // 取消计时器
          let cancel = (e) => {
            // 检查计时器是否有值
            if ( pressTimer !== null ) {
              clearTimeout(pressTimer);
              pressTimer = null;
            }
          }
          // 运行函数
          const handler = (e) => {
            // 执行传递给指令的方法
            binding.value(e)
          };  
          // 添加事件监听器
          el.addEventListener("mousedown", start);
          el.addEventListener("touchstart", start);
          // 取消计时器
          el.addEventListener("click", cancel);
          el.addEventListener("mouseout", cancel);
          el.addEventListener("touchend", cancel);
          el.addEventListener("touchmove", cancel);
          el.addEventListener("touchcancel", cancel);
        }
      })
    }
  }