javascript 我可以将`else if` 与三元运算符一起使用吗？
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can I use `else if` with a ternary operator?
提问by lologic
Can I only use ifand elsein a statement in ternary operator syntax or can I also somehow include an else if?
我可以只在三元运算符语法的语句中使用ifandelse还是我也可以以某种方式包含else if?
example:
例子：
if(a) {
x
}
else if(y) {
c
}
else {
b
}
回答by tadman
Unlike an ifwith optional elseor optional else ifbranches, a ternary operator has two and only two branches.
与ifwith optionalelse或 optionalelse if分支不同，三元运算符有两个且只有两个分支。
You can have else iflike functionality if you sub-branch the second clause:
else if如果您将第二个子句作为分支，您可以拥有类似的功能：
a ? b : (c ? d : e)
This is usually a bad ideaas ternary operations can be messy to start with and layering like this is usually an express train to unmaintainable code.
这通常是一个坏主意，因为三元运算开始时可能很混乱，而且像这样的分层通常是无法维护代码的快速列车。
It is much better to write:
最好这样写：
if (a) {
b
}
else if (c) {
{
d
}
else {
e
}
This is more verbose, but abundantly clear.
这更冗长，但非常清楚。
If you use ternaries too agressively you'll end up with code like:
如果你过于激进地使用三元组，你最终会得到如下代码：
a()?c?d?e:f:g:h?i(j?k:l?m:n):o
Where it's anyone's guess what's going on in there.
任何人都可以猜测那里发生了什么。
回答by Basti
You could stack multiple ternaries:
您可以堆叠多个三元组：
var x = (y) ? 1 : ( (z) ? 2 : 0 );
