JavaScript很有趣。考虑以下示例:
function changeStuff(a, b, c)
{
a = a * 10;
b.item = "changed";
c = {item: "changed"};
}
var num = 10;
var obj1 = {item: "unchanged"};
var obj2 = {item: "unchanged"};
changeStuff(num, obj1, obj2);
console.log(num);
console.log(obj1.item);
console.log(obj2.item);
产生输出:
10
changed
unchanged
实际上,这意味着如果你更改参数本身(如num
和一样obj2
),则不会影响输入该参数的项目。但是,如果你更改参数的INTERNALS
,则会传播回来(与一样obj1
)。