require: 'ngModel' in Angular 6/7+

Question

I'm working on a simple upper/lower case directive. Since I use ControlValueAccessor I would like to be able to require ngModel directive on a same host element where I apply my appCaseTo directive.

Is there way to do that in Angular?

How to require presence of certain directive from another directive?

Similar to AngularJS with require: 'ngModel' approach.

return {
    require: 'ngModel',
    link: function (scope, element, attrs, modelCtrl) {

Stackblitz project.

Answer 1

我不确定您要完成什么，但是您可以将ngModel“包括”到选择器中，如下所示：

  selector: '[ngModel][appCaseTo]',