component.js

import User from '../models/user';

const Validations_1 = buildValidations({
  username: validator('presence')
})

export default Ember.Component.extend({
  init() {
    this.super(...arguments);
    this.set('model', User.extend(Validations_1).create());
  }
})

component2.js

import User from '../models/user';

const Validations_2 = buildValidations({
  username: validator('length', {min: 5})
})

export default Ember.Component.extend({
  init() {
    this.super(...arguments);
    this.set('model', User.extend(Validations_2).create());
  }
})

user.js

const Validations = buildValidations({
  password: validator('presence')
})

export default DS.Model.extend(Validations, {
  // ...
});