How to call functions or watch variables in NODE-RED UI (angular.js)

angular js function call

<script>
(function(scope) {
    scope.name = "Here I am!!!";
    /* scope.fun = function(val){alert(val);return val}; */
    scope.$watch('msg.payload', function(newValue, oldValue) { 
        /* Do something clever here */ 
        if(!angular.equals(newValue, oldValue)){
            alert(newValue);
        }
    });
})(scope)
</script>
{{name+" "+msg.payload}}
<!-- {{fun(name)}} -->