为什么这个 ['3'|0 + 1] 按位不起作用？

Question

it seems this only work on "even" numbers:

"8"|0 + 1   // 9
"3"|0 + 1   // 3
("3"|0) + 1 // 4

but "3"|0 translates to the Integer 3 .

so what's going on here?
why does the second example acts like this in JS?

Answer 1

The precedence of + is higher than |.

So it's parsing like this:

"8" | (0 + 1) = "8" | 1 = 9
"3" | (0 + 1) = "3" | 1 = 3

Answer 2

+ has higher precedence than | so you need to put the brackets in to get the order of evaluation that you want.