技術標籤：jssonsole.log（）

console.log()，對於一般對於基本型別number、string、boolean、null、undefined 的輸出是可信的。但對於Object 等引用型別來說，則就會出現上述異常列印輸出。（除錯複雜資料型別時候通過打斷點來看即可）

正常預期

  <script>
    var arr1 = [1,2]
//     let arr1 = [
//       {id:1,name:1},
//       {id:2,name:2}
//     ]
    console.log(arr1);

    arr1[0]=111111
 
;

    console.log(arr1);

  </script>

列印結果

1.直接列印前後陣列的值 和預期結果一樣

  <script>
    // var arr1 = [1,2]
    let arr1 = [
      {id:1,name:1},
      {id:2,name:2}
    ]
    console.log(arr1);

    arr1[0]=111111;

    console.log(arr1);

  </script>

列印看到的結果是一致的

2.列印到具體的看卻不一致 和預期一樣

  <
 
script>
    // var arr1 = [1,2]
    let arr1 = [
      {id:1,name:1},
      {id:2,name:2}
    ]
    console.log(arr1[0]);

    arr1[0]=111111;

    console.log(arr1[0]);

  </script>

列印結果

3.做判斷 也是不一致 和預期一樣

<script>
    // var arr1 = [1,2]
    let arr1 = [
      {id:1,name:1},
      {id:2,name:
 
2}
    ]
    if (arr1[0] > 1) {
      console.log(1,arr1);
    }else {
      console.log(2,arr1);
    }

    arr1[0]=111111;

    // console.log(arr1);
    if (arr1[0] > 1) {
      console.log(3,arr1);
    }else {
      console.log(4,arr1);
    }

  </script>

列印結果