javascript 你如何增加一个knockout.js observable？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/9548859/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
How do you increment a knockout.js observable?
提问by Jeremy Smith
I'm finding this a strange place to be at a bit of a loss, but if I cant' do this:
我发现这是一个有点不知所措的奇怪地方，但如果我不能这样做：
koObserv(koObserv() + 1);
and a method is not provided, am I forced to do:
并且没有提供方法，我是否被迫这样做：
koObserv = ko.observable(koObserv() + 1)
This seems really clumsy.. is there another way that I'm missing?
这看起来真的很笨拙..还有我想念的另一种方式吗？
回答by John Earles
Here is a fiddle that demonstrates incrementing:
这是一个演示递增的小提琴：
http://jsfiddle.net/jearles/LbPDK/
http://jsfiddle.net/jearles/LbPDK/
As you can see self.num(self.num() + 1);does work.
如您所见，self.num(self.num() + 1);确实有效。
回答by Nerdroid
you could abstract these logic into an extend observable
你可以将这些逻辑抽象成一个扩展的可观察对象
ko.observable.fn.increment = function (value) {
this(this() + (value || 1));
};
var counter = ko.observable(0);
console.log(counter()); // 0
counter.increment();
console.log(counter()); // 1
counter.increment();
console.log(counter()); // 2
counter.increment(5);
console.log(counter()); // 7
回答by Rafael Eyng
I would suggest you to, if you use a lot of increment, create some helper function to do the increment and pass it the reference of your observable. You end up with more readable code.
如果您使用大量增量，我建议您创建一些辅助函数来进行增量并将其传递给您的 observable 的引用。您最终会得到更具可读性的代码。
JS:
JS：
var increment = function (observable) {
observable(observable() + 1);
};
var MyViewModel = function () {
this.num1 = ko.observable(0);
this.incrementNum = function (observable) {
// passing the observable by reference to the helper function
increment(observable);
}
}
HTML:
HTML:
<button data-bind="click: incrementNum.bind($root, num1)">
