gistfile1.txt

import { presence, length, confirmation, format} from 'ember-validations/validators';

errors: computed('name', 'email', 'password', 'passwordConfirmation', function() {
  let user = get(this, 'model');
  
  return user
    ::presence('name', 'email', 'password')
    ::length('password', { greaterThan: 8 })
    ::confirmation('password')
    ::format('email', /@/)
})

gistfile2.txt

const {
  isBlank
} = Ember;

export function presence(context, ...properties, options = {}) {
  let set = convertToSet(context);
  
  context.model.changedAttributes()
  ::Object.keys()
  ::intersect(properties)
  .forEach(function(prop) {
    if (isBlank(get(context.model, prop))) {
      setError(set, prop, 'presence');
    }
  });
}