與JS數組掙扎長度

Question

我有這樣的一段代碼，當你看到它，它看來，邏輯應該運行如下：

我創建3個空數組，我一個值添加到bankSelectedData，我打印出值，顯然bankSelectedData現在是1和bankSelectionArrayCurrent長度爲0，後來我說：

bankSelectionArrayPrevious = bankSelectionArrayCurrent; 

所以我轉向bankSelectionArrayPrevious到bankSelectionArrayCurrent。當我檢查bankSelectionArrayPrevious的大小是說'1'？這怎麼可能？

var bankSelectionArrayCurrent = new Array(); 
var bankSelectionArrayPrevious = new Array(); 
var bankSelectedData = new Array(); 
    bankSelectedData.push("value1"); 

alert("bankSelectionArrayCurrent length: "+bankSelectionArrayCurrent.length); 
alert("bankSelectedData length: "+bankSelectedData.length); 

if(bankSelectedData.length != bankSelectionArrayCurrent.length){ 
    bankSelectionArrayPrevious = bankSelectionArrayCurrent; 
    bankSelectionArrayCurrent.length = 0 

    alert("previousSize: "+bankSelectedData.length); 
    alert("currentSize: "+bankSelectionArrayCurrent.length); 
}​ 

感謝您的任何建議！

Answer 1

如果你有

alert("previousSize: "+bankSelectedData.length); 

也許你的意思是：

alert("previousSize: "+bankSelectionArrayPrevious.length); 

Answer 2

您的代碼永遠不會更改「bankSelectedData」，因此在添加第一個值後，其長度保持爲1。

您的代碼不包含任何調用「bankSelectionArrayPrevious」長度的alert()。

Answer 3

提醒您錯誤的。它應該是：

alert("previousSize: "+bankSelectionArrayPrevious.length);