對象是否以javascript的深層或淺層副本推入數組？

Question

很明顯的問題...當在javascript中的數組上使用.push（）時，對象是指針（淺）還是實際對象（深）推入數組， 而不管類型如何 。

Answer 1

這取決於您要推動什么。 對象和數組被推為指向原始對象的指針。 內置的原始類型（如數字或布爾值）將作為副本推送。 因此，由於不以任何方式復制對象，因此沒有深層或淺層副本。

這是顯示它的工作片段：

var array = [];
var x = 4;
let y = {name: "test", type: "data", data: "2-27-2009"};

// primitive value pushes a copy of the value 4
array.push(x);                // push value of 4
x = 5;                        // change x to 5
console.log(array[0]);        // array still contains 4 because it's a copy

// object reference pushes a reference
array.push(y);                // put object y reference into the array
y.name = "foo";               // change y.name property
console.log(array[1].name);   // logs changed value "foo" because it's a reference    

// object reference pushes a reference but object can still be referred to even though original variable is no longer within scope
if (true) {
    let z = {name: "test", type: "data", data: "2-28-2019"};
    array.push(z);
}

console.log(array[2].name);   // log shows value "test" since the pointer reference via the array is still within scope

Answer 2

jfriend00就在這里，但有一點澄清：這並不意味着您不能更改變量所指向的內容。 也就是說， y最初引用了您放入數組中的某個變量，但是您可以采用名為y的變量，將其與數組中的對象斷開連接，然后將y連接（即使其引用 ）， 而無需進行其他操作更改現在僅由數組引用的對象 。

http://jsfiddle.net/rufwork/5cNQr/6/

var array = [];
var x = 4;
var y = {name: "test", type: "data", data: "2-27-2009"};

// 1.) pushes a copy
array.push(x);
x = 5;
document.write(array[0] + "<br>");    // alerts 4 because it's a copy

// 2.) pushes a reference
array.push(y);
y.name = "foo";

// 3.) Disconnects y and points it at a new object
y = {}; 
y.name = 'bar';
document.write(array[1].name + ' :: ' + y.name + "<br>");   
// alerts "foo :: bar" because y was a reference, but then 
// the reference was moved to a new object while the 
// reference in the array stayed the same (referencing the 
// original object)

// 4.) Uses y's original reference, stored in the array,
// to access the old object.
array[1].name = 'foobar';
document.write(array[1].name + "<br>");
// alerts "foobar" because you used the array to point to 
// the object that was initially in y.

Answer 3

我們可以通過json stringify傳遞對象/數組來清除指針，然后解析

newobj.push(JSON.parse(JSON.stringify(obj)));

我希望它對某人有幫助，因此我發布了。