How to check if output binding is given?

Question

Examplecode:

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

the following post might answer this question: https://stackoverflow.com/a/38914917/2106610 — groetzi, Jul 20 '21 at 22:13

score 0 · Answer 1 · answered Oct 26 '16 at 09:01

0

If you want to check if binding is given just do:

   if(this.callback)
      return true
    else 
      return false

The value of the this.callback will be available in the component if the binding is there otherwise it wont be.

answered Oct 26 '16 at 09:01

Beslinda N.

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Not working because the binding is always a function. – tiktak Oct 26 '16 at 09:07

score 0 · Answer 2 · answered Mar 09 '17 at 20:34

0

If you change your binding to being optional, then it will be undefined if not supplied and you can check if it was given using the methods you've already mentioned.

bindings: {
  callback : '&?'
},

answered Mar 09 '17 at 20:34

Derenge

1

How to check if output binding is given?

2 Answers2