AngularJS 指令 - 将 ngModel 与 jQuery 小部件一起使用时的最佳实践 [英] AngularJS directives - best practices when using ngModel with jQuery widget

问题描述

这是我的问题.例如，我们有以下指令，它在幕后使用了一些 jQuery 小部件:

Here is my problem. For example, we have the following directive, which uses some jQuery widget behind the scenes :

module.directive('myWidget', [function() {
    return {
        require: "ngModel",
        restrict: "A",
        replace: true,
        templateUrl: "templates/myWidget.html",
        link: function(scope, element, attrs, ctrl) {
            element.widget_name().on('value_updated', function(event) {
                scope.$apply(function() {
                    var newModelValue = event.some_value;
                    ctrl.$setViewValue(newModelValue);
                });
            });

            scope.$watch(attrs["ngModel"], function(value){
                element.widget_name('set_value', value);
            });
        }
    };
}]);

因此，如果模型的值发生变化，那么使用 $watch 注册以监听模型变化的处理程序将被执行，因此，widget 的set_value"方法也将被执行.这意味着将触发 'value_updated' 事件.

So, if model's value changes, then the handler which is registered using $watch to listen for changes in model will be executed, and, consequently, widget's 'set_value' method will be executed too. This means that 'value_updated' event will be triggered.

我的问题是:在指令中实现类似行为以避免额外调用 DOM 事件处理程序和观察程序的最佳实践是什么?

My question is: what is the best practice to implement similar behavior in directives to avoid extra calls of DOM event handlers and watchers?

推荐答案

我建议实施 ctrl.$render() 而不是 scope.$watch().仅当 Angular 内部的某些内容更改模型时才应调用 $render.小提琴示例.

Instead of scope.$watch(), I suggest implementing ctrl.$render(). $render should only be called if something inside Angular changes the model. Fiddle example.

这解决了您没有提到的问题.不幸的是，它并没有解决您提到的问题.在小提琴中，绑定了一个 blur 事件，而不是一些 widget.on() 事件.也许这对你有用–即，仅在模糊时更新模型，而不是在每次击键时更新模型(但是，这假设您的小部件接受击键).

This solves a problem you did not mention. Unfortunately, it does not solve the problem you did mention. In the fiddle, a blur event is bound, rather than some widget.on() event. Maybe that would work for you – i.e., only update the model on blur, rather than every keystroke (this assumes your widget is accepting keystrokes, however).

也许您还可以要求小部件作者提供一个不会触发事件的设置"方法.然后可以在 $render() 方法中使用它.

Maybe you could also ask the widget author to provide a "set" method that does not trigger an event. Then that could be used in the $render() method.

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