Does CoffeeScript allow JavaScript-style == equali

2019-02-02 19:26发布

I love that CoffeeScript compiles == into the JavaScript === operator. But what if you want the original JS == semantics? Are they available? I've pored over the documentation and can't find anything enabling this.

More generally, is there a way to inline plain JS into my CoffeeScript code so that the compiler doesn't touch it?

I'd prefer to avoid editing the compiled JavaScript output, since I'm using Chirpy to auto-generate it in Visual Studio.

2条回答
迷人小祖宗
2楼-- · 2019-02-02 19:42

As a possible extension to this, is there a way to inline blocks of regular JS into CoffeeScript code so that it isn't compiled?

Yes, here's the documentation. You need to wrap the JavaScript code in backticks (`). This is the only way for you to directly use JavaScript's == in CoffeeScript. For example:

CoffeeScript Source [try it]
if `a == b`
  console.log "#{a} equals #{b}!"
Compiled JavaScript
if (a == b) {
  console.log("" + a + " equals " + b + "!");
}

The specific case of == null/undefined/void 0 is served by the postfix existential operator ?:

CoffeeScript Source [try it]
x = 10
console.log x?
Compiled JavaScript
var x;
x = 10;
console.log(x != null);
CoffeeScript Source [try it]
# `x` is not defined in this script but may have been defined elsewhere.
console.log x?
Compiled JavaScript
var x;
console.log(typeof x !== "undefined" && x !== null);
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仙女界的扛把子
3楼-- · 2019-02-02 20:07

This isn't exactly the answer but this problem came up for me because jQuery's .text() was including whitespace and 'is' was failing in Coffeescript. Get around it by using jQuery's trim function:

$.trim(htmlText) is theExpectedValue 
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