How to determine whether a checkbox is checked or not in Vue js

I just want to determine whether a checkbox is checked or not in Vue js 2. In jquery we have functions like $(‘input[type=checkbox]’).prop(‘checked’); which will return true if checkbox is checked or not. What is the equivalent function in Vue js.

Here is the scenario with code. Please note i am using laravel with its blade templates.

@foreach ($roles as $role)
   <input type="checkbox" v-on:click="samplefunction({{$role->id}})" v-model="rolesSelected" value="{{$role->id}}">                       
@endforeach  

The js part is

<script>
  var app = new Vue({
    el: '#app1',
    data: {
      rolesSelected:"",
    },
    methods : {
      samplefunction : function(value) {
        // Here i want to determine whether this checkbox is checked or not   
      }
    },
  });

</script>

Answer

You can do something like:

if(this.rolesSelected != "") {
   alert('isSelected');
}

or v-on:click="samplefunction({{$role->id}},$event)"

samplefunction : function(value,event) {
    if (event.target.checked) {
       alert('isSelected');
    }
}