@frozen class Foo {
  @configurable(false) @enumerable(true) method() {}
}

The core-decorators library includes a number of standalone decorators that are intended to work in vanilla JavaScript code.

An @deprecate decorator:

import { deprecate } from 'core-decorators';

class Person {
  @deprecate
  facepalm() {}

  @deprecate('We stopped facepalming')
  facepalmHard() {}

  @deprecate('We stopped facepalming', { url: 'http://knowyourmeme.com/memes/facepalm' })
  facepalmHarder() {}
}

let person = new Person();

person.facepalm();
// DEPRECATION Person#facepalm: This function will be removed in future versions.

person.facepalmHard();
// DEPRECATION Person#facepalmHard: We stopped facepalming

person.facepalmHarder();
// DEPRECATION Person#facepalmHarder: We stopped facepalming
//
//     See http://knowyourmeme.com/memes/facepalm for more details.
//

A throttling decorator:

import { throttle } from 'core-decorators';

class Editor {

  content = '';

  @throttle(500, { leading: false })
  updateContent(content) {
    this.content = content;
  }
}

A mixin class decorator:

import { mixin } from 'core-decorators';

const SingerMixin = {
  sing(sound) {
    alert(sound);
  }
};

const FlyMixin = {
  // All types of property descriptors are supported
  get speed() {},
  fly() {},
  land() {}
};

@mixin(SingerMixin, FlyMixin)
class Bird {
  singMatingCall() {
    this.sing('tweet tweet');
  }
}

var bird = new Bird();
bird.singMatingCall();
// alerts "tweet tweet"

A decorator using console.time to time a function:

class Bird {
  @time('sing')
  sing() {
  }
}

var bird = new Bird();
bird.sing(); // console.time label will be 'sing-0'
bird.sing(); // console.time label will be 'sing-1'

var x = 1;

import { computedFrom } from 'aurelia-framework';

export class Welcome{
  firstName = 'John';
  lastName = 'Doe';

  @computedFrom('firstName', 'lastName')
  get fullName(){
    return `${this.firstName} ${this.lastName}`;
  }
}

import { customElement, useShadowDOM, bindable } from 'aurelia-framework';

@customElement('nav-bar')
export class NavBar {}

@useShadowDOM
@customElement('my-expander')
export class Expander {
  @bindable isExpanded = false;
  @bindable header;
}

import Ember from 'ember';
import computed from 'ember-computed-decorators';

export default class extends Ember.Component {
  @computed('first', 'last')
  name(first, last) {
    return `${first} ${last}`;
  }
};

import Ember from 'ember';
import computed, { readOnly } from 'ember-computed-decorators';

export default class extends Ember.Component {
  @readOnly
  @computed('first', 'last')
  name(first, last) {
    return `${first} ${last}`;
  }
};

import DS from 'ember-data';
import {
  attr,
  hasMany
} from "ember-computed-decorators/ember-data";

export default class extends DS.Model {
  @attr firstName,
  @hasMany users
};

import Ember from 'ember';
import { alias } from 'ember-computed-decorators';
export default class extends Ember.Component {
  person: {
    first: 'Joe'
  }

  @alias('person.first') firstName
};

import Ember from 'ember';
import { intersect } from 'ember-computed-decorators';

export default class extends Ember.Component {
  likes = [ 'tacos', 'puppies', 'pizza' ];
  foods = [ 'tacos', 'pizza' ];

  @intersect('likes', 'foods') favoriteFoods; // ['tacos', 'pizza']
};

@Component({
  selector: 'talk-cmp',
  directives: [FormattedRating, WatchButton, RateButton],
  templateUrl: 'talk_cmp.html'
})
class TalkCmp {
  @Input() talk: Talk;
  @Output() rate: EventEmitter;
  // ...
}