angularjs - How to check if output binding is given? -

how check if output binding given?

examplecode:

angular.module('tester', []); angular.module('tester').component('test', {     template: '<h3></h3>',     bindings: {       callback : '&'     },     controller: function() {        // how check if callback binding given?        // typeof this.callback === 'function' returns true        // angular.isfunction(this.callback) returns true      } });  

if want check if binding given do:

   if(this.callback)       return true     else        return false 

the value of this.callback available in component if binding there otherwise wont be.