带函数的JavaScript三元运算符示例 [英] JavaScript ternary operator example with functions

问题描述

我正在使用jQuery 1.7.1

I am using jQuery 1.7.1

我刚开始使用JavaScript三元运算符来替换简单的if / else语句。我在几个地方成功地做到了。当我成功地做出其他工作的时候，当我确定不会这样做时，我很惊讶，但我还是尝试过。

I am just starting to use the JavaScript ternary operator to replace simple if/else statements. I have done so successfully in several places. I was surprised when I successfully made something else work when I thought for sure it wouldn't, but I tried anyway.

这是原始声明：

function updateItem() {
    $this = $(this);
    var IsChecked = $this.hasClass("IsChecked");
    if (IsChecked == true){
        removeItem($this);
    } else {
        addItem($this);
    }
}

这是使用三元运算符的相同函数：

Here's the same function using the ternary operator:

function updateItem() {
    $this = $(this);
    var IsChecked = $this.hasClass("IsChecked");
    (IsChecked == true) ? removeItem($this) : addItem($this);
}

我很惊讶因为我看到的所有例子都只是设置变量像这样：

I was surprised because all of the examples I saw being used were merely setting variables like this:

x = (1 < 2) ? true : false;

我的问题是这是否是正常使用，是否适用于大多数JavaScript版本？它会在哪里失败？还有其他不太明显的用途吗？

My question is whether this is "normal" use and will it work in most versions of JavaScript? Where will it fail? Are there other less obvious uses for it?

更新 - 感谢真实世界的建议!!!

我使用它作为我的函数：

I am using this as my function:

function updateItem() {
    $this = $(this);
    $this.hasClass("IsChecked") ? removeItem($this) : addItem($this);
}

推荐答案

嘿，有一些漂亮的在你的问题中激动地使用三元语法;我最喜欢最后一个......

Heh, there are some pretty exciting uses of ternary syntax in your question; I like the last one the best...

x = (1 < 2) ? true : false;

这里使用三元是完全不可能的 - 你可以简单地写一下

The use of ternary here is totally uncessesary - you could simply write

x = (1 < 2);

同样，三元语句的condition元素总是被评估为布尔值，因此你可以表达：

Likewise, the condition element of a ternary statement is always evaluated as a Boolean value, therefore you can express:

(IsChecked == true) ? removeItem($this) : addItem($this);

简单如下：

(IsChecked) ? removeItem($this) : addItem($this);

事实上，我还会删除 IsChecked 暂时离开你：

Infact, I would also remove the IsChecked temporary as well which leaves you with:

($this.hasClass("IsChecked")) ? removeItem($this) : addItem($this);

至于这是可接受的语法，它肯定是！这是将四行代码减少为一行而不影响可读性的好方法。我给你的唯一建议是避免在同一行上嵌套多个三元语句（这就是疯狂！）

As for wether this is acceptable syntax, it sure is! It's a great way to reduce four lines of code into one without impacting readability. The only word of advice I would give you is to avoid nesting multiple ternary statements on the same line (that way lies madness!)

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