I had to change fail on resolve as well to get Promise to work

[born2net]

export default function NameTakenValidator(control:Control):Promise<ValidationResult> {
    let q = new Promise((resolve, reject) => {
        setTimeout(() => {
            if (control.value === 'Sean') {
                resolve({"taken": true});
            } else {
                resolve(null);
            }
        }, 1000)
    });
    return q;
}

[born2net]

by the way if you want to see a massive ng2 app check out: http://ng2.javascriptninja.io