how to create custom validators in Angular 2 ES5? - validation

Question

I'm trying to create a custom validator for Angular 2 using ES5. I can't find a sample online, and the cheatsheet of the documentation doesn't help and it's not documented for ES5 at all. Also, I can't transpile completely from given examples of TypeScript to ES5. Let's say the validator is a simple code validator that more than a simple Regular Expression match, should check for CRC too. Thus it can't be accomplished with built-in pattern validator of Angular 2.
Here's my code that I've tried:
var securityCode = ng.core.Directive({
selector: '[securityCode][ngModel]',
providers: [
{
provide: ng.forms.NG_VALIDATORS,
useExisting: securityCode,
multi: true
}
]
}).Class({
constructor: function() {
console.log('securityCode');
},
validate: function(value){
console.log('validate...');
},
validator: function(value){
console.log('validator...');
}
});
and here's how I want to use it:
<input mdInput type="text" requried securityCode />
I'm stuck now, I can't go further as this doesn't work because I get Cannot read property 'validate' of undefined exception, and I have no idea what to do next.