为什么reference = null 不影响被引用的对象? [英] Why does reference = null not affect the referenced object?

问题描述

我知道这行得通，但我不知道为什么或这样做的原因:

I know this works, but I don't know why or the reasoning behind why it was made to work this way:

var foo = [5, 10];
var bar = foo;
console.log(foo); //[5, 10]
console.log(bar); //[5, 10]
bar[0] = 1; 
console.log(foo); //[1, 10]
bar = null;
console.log(foo); //[1, 10]

我希望不仅 bar 变为 null，而且 foo 也会变为 null.我希望得到一些帮助来理解这一点.

I would have expected not just bar to become null, but foo as well. I'd love some help understanding this.

推荐答案

区别在于 重新绑定和变异操作.

bar[0] = 1

正在变异；它会影响 bar 指向的对象.

is mutating; it affects the object that bar points to.

bar = null

正在重新绑定；它只会影响标识符 bar 的含义.

is rebinding; it just affects what the identifier bar means.

这篇关于为什么reference = null 不影响被引用的对象?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！