05-扩展运算符

一、扩展运算符

  <script>
        //扩展运算符可以将数组或者对象转为用逗号分隔的参数序列
        let arr = [1, 2, 3]
        // ...arr //1,2,3
        console.log(...arr); //1 2 3
        console.log(1, 2, 3);
  </script>

二、应用-合并数组

    <script>
        //扩展运算符可以应用合并数组
        //方法一:
        let arr1 = [1, 2, 3]
        let arr2 = [4, 5, 6]
        let arr3 = [...arr1, ...arr2]
        console.log(arr1);
        console.log(arr2);
        console.log(arr3);

        //方法二:
        arr1.push(...arr2);
        console.log(arr1);
    </script>

三、应用-伪数组转真数组

    <div>1</div>
    <div>2</div>
    <div>3</div>
    <div>4</div>
    <div>5</div>
    <div>6</div>
    <script>
        //利用扩展运算符将伪数组 转为真数组
        var divs = document.querySelectorAll('div')
        console.log(divs);
        let arr = [...divs]
        console.log(arr);
    </script>