javascript - [b][b = a,0] 如何在 a 和 b 之间交换？

Question

作为gdoron指出，

var a = "a";
var b = "b";

a = [b][b = a,0];

会交换a和b，虽然看起来有点hacky，但是已经引发了我的好奇心，我很好奇怎么运行的。这对我来说没有任何意义。

Answer 1

var a = "a";
var b = "b";

a = [b][b = a, 0];

让我们把最后一行分成几个部分:

[b]       // Puts b in an array - a safe place for the swap.
[b = a]   // Assign a in b
[b = a,0] // Assign a in b and return the later expression - 0 with the comma operator.

所以最后是 a =[b][0] - [b] 数组中的第一个对象 => b 赋值到 a

Live DEMO

阅读@am not I am comments in this question:
When is the comma operator useful?
这是他的代码...