Is it a bug? - I can not get the correct state of the switchery when loading the page for the first time

[martinmurciego]

The initial state of the switchery is always false when it is obtained by Javscript / jQuery code, when the page is loaded or rendered having this checked / unchecked value preset in the HTML code.
I want to retrieve the current state (checked / unchecked) to use in a validation of data entered into a form.

Javascript / Jquery 3.2.1

if( $('#checkIsIndoor').prop('checked')===true) {
if ( $("#inputHeight").val().trim() === '' ){
                showError('inputHeight', 'As it is an Interior Meeting Space you must enter the height in meters.');
                todoOk = false;
            }
            else{
                clearErrors('inputHeight');
            }
}

HTML

<div class="form-group">
    <label>
        <input id="checkEsInterior" name="esInterior" type="checkbox" class="js-switch" checked="" data-switchery="true" style="display: none;"> Es Interior?
    </label>
</div>

However, after clicking on the Switchery and re-executing the code that gets the value of the Switchery / Checkbox, the value is correct.
The only thing that works for me correctly and should not be is:

if ($("#checkEsInterior + span.switchery-default").css('background-color')=="rgb(38, 185, 154)"){
if ( $("#inputHeight").val().trim() === '' ){
                showError('inputHeight', 'As it is an Interior Meeting Space you must enter the height in meters.');
                todoOk = false;
            }
            else{
                clearErrors('inputHeight');
            }
}

The color rgb (38, 185, 154) is the checked status color of the Switchery by default.

Why does this happen?