How to use ng-disabled with jade templates

Question

Now I work with nodejs and investigate angularjs for fun) But I have some problem I want to add file upload for my blog project and i did it) So I want show upload button only if user select some file. It is not a problem with jQuery but I want to know how to do it with angular. So here I have more problems

Here is Jade template

form(method="post",enctype="multipart/form-data", action="/imageUpload")
              label Select image 
              input(type='file',name='image',onchange="angular.element($(this)).scope().inputChange()")
              button.btn.btn-primary(type='submit,ng-disabled='{{isEnable}})#uploadBtn Upload Image 

here is my work jQueryCod for validate

function UserController($scope)
{
    var sizeInput = $("input[type='file']").val().length;
    isEnable = sizeInput === 0 ;
    $( "#uploadBtn" ).toggle( isEnable )   
    $scope.inputChange = function(){
        sizeInput = $("input[type='file']").val().length;
        isEnable = !(sizeInput > 0);
        $( "#uploadBtn" ).toggle( isEnable );
    }
}

Of cource I can use only jquery - but I want to know how angular works.

So I want to use ng-disbled - but it doesn't work correctly. At first load it takes position true - and it all - it doesn't change

function UserController($scope)
{       
    var sizeInput = $("input[type='file']").val().length;
    $scope.isEnable = sizeInput === 0 ;       
    $scope.inputChange = function(){
        sizeInput = $("input[type='file']").val().length;
        myScope.isEnable = !(sizeInput > 0);

    }
}

I have found answer that here we mast use not {{ isEnable}} but just ng-disabled='isEnable' without parentheses but how inject it to jade???

Answer 1

Remove the {{}} since you're already writing in Angular inside ng-* attributes:

ng-disabled='{{isEnable}}

To:

ng-disabled='isEnable'

Answer 2

Use ng-show

button.btn.btn-primary(type='submit,ng-show='isEnable')#uploadBtn Upload Image

This will tell angular to show your button only when isEnable is true. When it's false, the button won't be shown.