是否有可能以某种方式替换作为函数参数的原始对象？

Question

function f(obj) {
    obj = _ => console.log(
        'LOCAL object was replaced, how to replace from the outer scope?');
}

f(fetch);

据我所知，这是不可能的，但也许存在一些技巧？

Answer 1

不，你不能那样做。

相反，您最好的选择是 return 新对象，并在调用时重新分配：

function f(obj) {
    return _ => console.log(
        'LOCAL object was replaced, how to replace from the outer scope?');
}

fetch = f(fetch);

或者，您可以传入将目标对象作为其状态的一部分的容器，并更新该容器的状态：

function f(container) {
    container.obj = _ => console.log(
        'LOCAL object was replaced, how to replace from the outer scope?');
}

var c = {obj: fetch};    
f(c);
// ...use c.obj...

或

function f(container) {
    container[0] = _ => console.log(
        'LOCAL object was replaced, how to replace from the outer scope?');
}

var c = [fetch];    
f(c);
// ...use c[0]...

是否有可能以某种方式替换作为函数参数的原始对象？

Is it possible somehow to replace original object that is argument to a function?

javascript

pass-by-reference