User.ts

export class User {
	userPromise() {
		return new Promise((resolve, reject) => {
			if(1 === 1) {
				return resolve([{name: 'Iparra'}])
			}
			return reject({msg: 'error'});
		})
	}
}

let user = new User();
let promise = user.getUserPromise();

promise.then(user => {
	console.log(user[0]); //{name: 'Iparra'}
}).catch(error => {
	console.log(error); //Uncaught {msg: "error"}
});