JSFiddle - React, Tailwind, and code Playground

HTML

<div ng-app="app">
    <input type="checkbox" ng-model="checkbox" cd-true-value="1" cd-false-value="0" />
    {{checkbox}}
</div>

JavaScript

angular.module('app', []).directive('cdTrueValue', [function() {
  return {
    restrict: 'A',
    require: 'ngModel',
    link: function(scope, element, attrs, ngModel) {
      ngModel.$parsers.push(function(v){
        return v ? scope.$eval(attrs.cdTrueValue) : scope.$eval(attrs.cdFalseValue);
      });
    }
  };
}])