您可以观看触发指令的属性吗？

Question

Is it possible to watch the attribute which triggered the directive?

export function minDirective(): ng.IDirective {
  return {
    restrict: 'A',
    require: 'ngModel',
    link: (scope, elem, attr, ctrl) => {
      scope.$watch(<name of the attribute>, () => {
        // Do something
      });
    }
  };
}

I'd like to listen to bb-civic-registration-number-format attribute the example below, except I have no idea it's named that way by the programmer reusing my directive:

I'm trying to create a validation directive which would take an arbitrary expression and use it for validation. A typical example is ngMin and ngMax except I'd like to implement similar functionality for an arbitrary input type:

<input type="number" ng-model="someModel" />
<input type="text" myprefix-max="someModel*0.5" />

Answer 1

If I understand question properly you can use the attribute value and [] notation.

<element my-directive scope-var="controllerScopePropertyName"></element >

JS

export function myDirective(): ng.IDirective {
  return {
    restrict: 'A',
    require: 'ngModel',
    link: (scope, elem, attr, ctrl) => {

      // using ES5 syntax
      scope.$watch(function(){
          return scope[attr.scopeVar];
      }, function(newVal,oldVal){
         // do something
      });
    }
  };
}

Alternatively just set up isolated scope and bind directly to the controller

Answer 2

You can actually get the name of your directive in the compile function, which should give you the ability to look up the value by comparing it to the attribute collection.

compile: function (elem, attrs) {
    console.log(this.name);
}