Compile time checks using Typescript in Meteor 1.10

Hi all,

question about using Typescript in Meteor 1.10. I am quite familiar with ES2015+ and also Meteor, but not with Typescript.

In my main.ts I have the following:

import { Meteor } from 'meteor/meteor';
import { Accounts } from 'meteor/accounts-base'

interface User {
  username: string;
  password: string

Meteor.startup(() => {
  if(Meteor.users.find().count() === 0) {
    try {
      const newUser: User = {username: false, password: "admin123"};
      const result: string = Accounts.createUser(newUser);
    } catch (e) {

My expectation is that Typescript should fail this at compile time, because I am defining username in the newUser object with a boolean instead of the string defined in the User interface. But the only error I get is from the check during Accounts.createUser call. Can someone explain why a compile-time error is not shown?