更新關聯數組中每個項目的值

Question

我有一個JavaScript關聯數組，說：

var myArray = new Object();
myArray["id1"] = "completed";
myArray["id2"] = "notCompleted";
myArray["id3"] = "started";

如何更新此數組中每個項目的值，以便輸出應為：

myArray["id1"] = "newValue";
myArray["id2"] = "newValue";
myArray["id3"] = "newValue";

Answer 1

使用Object.keys()獲取所有屬性名稱數組，然后使用Array#forEach方法遍歷它們，更新屬性值。

 var myArray = new Object(); myArray["id1"] = "completed"; myArray["id2"] = "notCompleted"; myArray["id3"] = "started"; Object.keys(myArray).forEach(function(k) { myArray[k] = 'newVal'; }); console.log(myArray); 

---

使用while循環的更快方法。

 var myArray = new Object(); myArray["id1"] = "completed"; myArray["id2"] = "notCompleted"; myArray["id3"] = "started"; var names = Object.keys(myArray), i = names.length; while (i--) { myArray[names[i]] = 'newVal'; }; console.log(myArray); 

Answer 2

• 用於循環
• 始終建議使用hasOwnProperty來僅在非繼承屬性上進行迭代。

 var myArray = new Object(); myArray["id1"] = "completed"; myArray["id2"] = "notCompleted"; myArray["id3"] = "started"; for (var prop in myArray) { if (myArray.hasOwnProperty(prop)) { myArray[prop] = 'newValue'; } } console.log(myArray);