角JS指令，改变一个2路数据链接功能结合 [英] Angular JS directive, change a 2 way data binding in the link function

问题描述

我试图创造一个角指令，我可以通过一个单一的选择对象，或者通过某些属性设置的选项。这里是那种code的一个例子：

I'm trying to create an angular directive where I can set the options either via a single options object, or via some attributes. Here is an example of the kind of code:

app.directive('testElement', [function () {
    return {
        restrict: "E",
        scope: {
            options: "="
        },
        template: "<p><span>Name: </span>{{ options.name }}</p>",
        link: function (scope, element, attrs) {
            scope.options = scope.options || {};
            if (attrs.name)
                scope.options.name = attrs.name;
        }
    };
}]);

这工作得很好，因为如果我通过在一个名字通过选项属性名值显示。但是，如果我通过name属性传递一个名字，即使连接功能不修改选项，该值不渲染。

This works fine, in that the name value is displayed if I pass in a name via the options attribute. But if I pass a name via the name attribute, even though the link function does modify options, the value is not rendered.

http://plnkr.co/edit/IMVZRdAW2a5HvSq2WtgT?p=$p$ PVIEW

我觉得我失去了一些东西在数据绑定选项2路如何工作的基础。

I feel like I'm missing something fundamental in how the 2 way data binding of options works.

推荐答案

如果您没有通过双向数据绑定，角生气：

If you don't pass the two way data binding, angular gets angry:

<一个href=\"https://github.com/angular/angular.js/issues/1435\">https://github.com/angular/angular.js/issues/1435

使用可选的绑定（=）：

Use optional binding (=?):

app.directive('testElement', [function () {
    return {
        restrict: "E",
        scope: {
            options: "=?"
        },
        template: "<p><span>Name: </span>{{ options.name }}{{ test }}</p>",
        link: function (scope, element, attrs) {
            scope.options = scope.options || {};
            if (attrs.name)
                scope.options.name = attrs.name;
        }
    };
}]);

或者，如果你使用的是棱角分明，使用$的eval对ATTRS旧版本。选项​​：

Or if you are using an older version of angular, use $eval on attrs. options:

app.directive('testElement', [function () {
    return {
        restrict: "E",
        //Still can create isolate scope to not clobber parent scope variables.
        scope: {},
        template: "<p><span>Name: </span>{{ options.name }}{{ test }}</p>",
        link: function (scope, element, attrs) {
            scope.options = scope.$eval(attrs.options) || {};
            if (attrs.name)
                scope.options.name = attrs.name;
        }
    };
}]);

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