Deprecation Guide for Computed Property Overridability

Ember's computed properties are overridable by default if no setter is defined:

const Person = EmberObject.extend({
  firstName: 'Diana',
  lastName: 'Prince',

  fullName: computed('firstName', 'lastName', function() {
    return `${this.firstName} ${this.lastName}`;
  })
});

let person = Person.create();
person.fullName; // Diana Prince

person.set('fullName', 'Carol Danvers');

person.set('firstName', 'Bruce');
person.set('lastName', 'Wayne');


person.fullName; // Carol Danvers

This behavior is bug prone and has been deprecated. readOnly(), the modifier that prevents this behavior, will be deprecated once overridability has been removed.

If you still need this behavior, you can create a setter which accomplishes this manually:

const Person = EmberObject.extend({
  firstName: 'Diana',
  lastName: 'Prince',

  fullName: computed('firstName', 'lastName', {
    get() {
      if (this._fullName) {
        return this._fullName;
      }

      return `${this.firstName} ${this.lastName}`;
    },

    set(key, value) {
      return this._fullName = value;
    }
  })
});