Array.splice（）行爲不如預期

Question

我遇到了Array.splice()函數的問題。當我將一個對象添加到一個數組中時，將它重新拼接出來，會丟失它的所有屬性。爲什麼？

Demo。

// create a new object named myObj, test to see if all properties are intact 
var myObj = { 
    prop1: 5, 
    prop2: 3, 
    prop3: 9 
}; 

for(key in myObj) { 
    document.write(key + " <br>"); 
} 

// they are, prepare a break-line 
document.write("---<br>");  

// okay, so I'm adding the object to a newly created array 
var myArr = new Array(); 
myArr.push(myObj); 

// watch what happens if I splice the obj back out of the array 
var mySplicedObj = myArr.splice(0, 1); 

// why doesn't this work? 
document.write(mySpliceObj.prop1); 

// this shows that myObj has lost all its properties when spliced! 
for(key in mySplicedObj) { 
    document.write(key); 
} 

// how is this happening, and why? 
​ 

Answer 1

splice()返回一個數組，則可以通過使用mySplicedObj[0]訪問該對象。