我可以使用带有两个变量的case / switch语句吗？ [英] Can I use a case/switch statement with two variables?

问题描述

对于JavaScript来说，我是一个新手，我的理解是使用一个SWITCH / CASE语句比一大堆IF语句更快。

I am a newbie when it comes to JavaScript and it was my understanding that using one SWITCH/CASE statements is faster than a whole bunch of IF statements.

但是，我想使用带有两个变量的SWITCH / CASE语句。

However, I want to use a SWITCH/CASE statement with two variables.

我的网络应用程序有两个滑块，每个都有五个状态。我希望行为基于这两个变量的状态。很明显，这是很多IF / THEN语句的全部内容。

My web app has two sliders, each of which have five states. I want the behavior to be based on the states of these two variables. Obviously that is a whole heck of a lot of IF/THEN statements.

我想做的一种方法是将两个变量连接成一个然后我可以SWITCH / CASE那个。

One way I thought about doing it was concatenating the two variables into one and then I could SWITCH/CASE that.

有没有更好的方法来使用两个变量来完成SWITCH / CASE？

Is there a better way of accomplishing a SWITCH/CASE using two variables ?

谢谢！

推荐答案

按位运算符怎么样？而不是字符串，你正在处理enums，它看起来更优雅。

How about a bitwise operator? Instead of strings, you're dealing with "enums", which looks more "elegant."

// Declare slider's state "enum"
var SliderOne = {
    A: 1,
    B: 2,
    C: 4,
    D: 8,
    E: 16
};

var SliderTwo = {
    A: 32,
    B: 64,
    C: 128,
    D: 256,
    E: 512
};

// Set state
var s1 = SliderOne.A,
    s2 = SliderTwo.B;

// Switch state
switch (s1 | s2) {
    case SliderOne.A | SliderTwo.A :
    case SliderOne.A | SliderTwo.C :
        // Logic when State #1 is A, and State #2 is either A or C
        break;
    case SliderOne.B | SliderTwo.C :
        // Logic when State #1 is B, and State #2 is C
        break;
    case SliderOne.E | SliderTwo.E :
    default:
        // Logic when State #1 is E, and State #2 is E or
        // none of above match
        break;


}

我同意其他人，25例在一个switch-case逻辑中并不是太漂亮，而且在某些情况下if-else可能会看起来更好。无论如何。

I however agree with others, 25 cases in a switch-case logic is not too pretty, and if-else might, in some cases, "look" better. Anyway.

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