什么是AngularJS计算观察到了淘汰赛的可写的模拟？ [英] What is the analog for Knockout's writable computed observable in AngularJS?

问题描述

我用KnockoutJS在我的项目，但要学会AngularJS，因为它有很多好吃的功能，淘汰赛没有。
所以我感兴趣的重写采用了棱角分明一些我的code的。但我不知道该怎么办，我在淘汰赛使用一些简单的事情。
例如，淘汰赛有计算观测的一个特点。这个很酷！
我已经发现，我可以用一个简单的函数。但淘汰赛提供了写的功能，它向计算观测，如：

I use KnockoutJS in my projects, but want to learn AngularJS as it has a lot of tasty features that Knockout doesn't have. So I'm interested in rewriting some of my code using Angular. But I don't understand how to do some simple things that I use in Knockout. For example, Knockout has a feature of computed observables. It's cool! I've already found that I can use a simple function instead. But Knockout provides "write" function to a computed observables, like:

var first_name = ko.observable('John'),
    last_name = ko.observable('Smith'),
    full_name = ko.computed({
        read: function(){
            return first_name() + ' ' + last_name();
        },
        write: function(new_value){
            var matches = new_value.match(/^(\w+)\s+(\w+)/);

            first_name(matches[1]);
            last_name(matches[2]);
        }
    });

在此的jsfiddle code： http://jsfiddle.net/Girafa/QNebV/1/

This code on JSFiddle: http://jsfiddle.net/Girafa/QNebV/1/

这code可让我当我改变FULL_NAME一更新FIRST_NAME和姓氏观测。如何它可以使用AngularJS做什么？正在检查生存与参数的函数？像这样的事情？

This code allows me to update the "first_name" and "last_name" observables when I change the "full_name" one. How it can be done using AngularJS? A function with an argument being checked for existence? Something like this?

first_name = 'John';
last_name = 'Smith';
full_name = function(value){
    if (typeof value != 'undefined')
    {
        // do the same as in the Knockout's write function
    }
    else
    {
        // do the same as in the Knockout's read function
    }
}

什么是最好的做法是什么？

What is the best practice?

推荐答案

我已经找到这样的解决方案：的http：//的jsfiddle。净/ Girafa / V8BNc /

I've found such a solution: http://jsfiddle.net/Girafa/V8BNc/

而是采用了棱角分明$表的方法，我们设置本地JavaScript fullName属性的getter和setter：

Instead of using angular $watch method, we set native javascript getter and setter of the fullName property:

Object.defineProperty($scope, 'fullName', {
    get: function(){
        #...
    },
    set: function(newValue){
        #...
    }
})

想到这是我不需要做任何特殊的观察家在code更方便。但我不知道浏览器支持这种解决方案的。

Think this is more convenient as I don't need to make any special watchers in the code. But I don't know about browser support of this solution.

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