vue 实用指令

1. 限制input 只允许输入正整数
   

   <input type="number" v-number-only >

   directives: {
           // 限制input 只允许输入正整数
           'number-only': {
             bind(el) {
               el.addEventListener('input', function() {
                 let val = this.value.replace(/[^\d]/g, '');
                 if (val === '') {
                   this.value = '';
                 } else {
                   val = val.replace(/^0+/, '') || '0';
                   this.value = val;
                 }
                   // 异步派发事件
                   setTimeout(() => {
                     const event = new Event('input', { bubbles: true });
                     this.dispatchEvent(event);
                   }, 0);
               });
             }
           }
         }