無法遍歷 Javascript Object

Question

我有以下object（失眠歸來）

[
  {
    "field": 10.5,
    "this_is_a_bool": 1,
    "name": "",
    "data": "2018-05-22T03:00:00.000Z",
    "field2": null
  },
  {
    "field": 5.3,
    "this_is_a_bool": 0,
    "name": "Slim Shady",
    "data": "2020-01-22T04:45:00.000Z",
    "field2": null
  }
]

問題是我不能迭代那些“值集”，所以我可以編輯它們。

做這樣的事情：

for (const val in myObj) {
   if (val.field2 === null) {   
      val.field1 = 'flag - ' + val.field1
   }
}

我試過的：

for (const val in myObj)
for (const val of myObj)
const [key,value] of Object.entries(myObj)

錯誤：有時它說myObj is not iterable ，有時代碼被忽略。

Answer 1

你為什么不使用簡單的.map() ：

 const src = [{"field":10.5,"this_is_a_bool":1,"name":"","data":"2018-05-22T03:00:00.000Z","field2":null},{"field":5.3,"this_is_a_bool":0,"name":"Slim Shady","data":"2020-01-22T04:45:00.000Z","field2":null}], result = src.map(({field, field2, ...rest}) => ({ field: field2 === null? `flag-${field}`: field, field2, ...rest })) console.log(result)

 .as-console-wrapper{min-height:100%;}

Answer 2

或...如果您仍想使用 for 循環...（在您的示例中 val 是關鍵）

 var myObj = [ { "field": 10.5, "this_is_a_bool": 1, "name": "", "data": "2018-05-22T03:00:00.000Z", "field2": null }, { "field": 5.3, "this_is_a_bool": 0, "name": "Slim Shady", "data": "2020-01-22T04:45:00.000Z", "field2": null } ]; for (const val in myObj) { if (myObj[val].field2 === null){ myObj[val].field = 'flag - ' + myObj[val].field; } } console.log(myObj);