在 JavaScript switch 语句中假设严格比较是否安全？
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Is it safe to assume strict comparison in a JavaScript switch statement?
提问by Paul
I have a variable that can either be boolean false, or an integer (including 0). I want to put it in a switch statement like:
我有一个可以是 booleanfalse或整数（包括 0）的变量。我想把它放在一个 switch 语句中，如：
switch(my_var){
case 0:
// Do something
break;
case 1:
// Do something else
break;
case false:
// Some other code
}
In my tests in Google Chrome, it seems to work perfectly, but I'm a little nervous to use it because I'm afraid that in some browsers, if my_varis false, it might execute the first case since 0 == false.
在我在 Google Chrome 中的测试中，它似乎工作得很好，但我使用它有点紧张，因为我担心在某些浏览器中，如果my_var是false，它可能会执行自0 == false.
I'm just wondering if there is anything official in JavaScript that says the switch statement will use strict comparison such that 0 !== false, but I can't find anything myself, and I'm not sure if this will work well in different JavaScript engines. Does anybody know if the comparison done by a switch statement is guaranteed to be strict?
我只是想知道 JavaScript 中是否有任何官方声明 switch 语句将使用严格比较0 !== false，但我自己找不到任何东西，我不确定这是否会在不同的 JavaScript 引擎中运行良好。有人知道 switch 语句所做的比较是否保证严格？
采纳答案by Federico Lebrón
Take a look at ECMA 262, section 12.11, the second algorithm, 4.c.
看看ECMA 262，第 12.11 节，第二种算法，4.c。
c. If input is equal to clauseSelector as defined by the === operator, then...
C。如果输入等于由 === 运算符定义的子句选择器，则...
回答by Halcyon
http://qfox.nl/notes/110answers your question. (This guy knows a lot about the nitty gritty of JavaScript)
http://qfox.nl/notes/110回答您的问题。（这家伙对 JavaScript 的本质了解很多）
Switches in Javascript use strict type checking (===). So you never have to worry about coercion, which prevents a few wtfjs :). If on the other hand you were counting on coercion, tough luck because you can't force it.
Javascript 中的开关使用严格的类型检查 (===)。所以你永远不必担心强制，这会阻止一些 wtfjs :)。另一方面，如果你指望强制，那么运气不好，因为你不能强迫它。
回答by ma11hew28
Yes, switch"[uses] the strict comparison, ===".
是的，switch“[使用] 严格比较，===”。
Source: switch - JavaScript | MDN
