import { get, set, computed, isElementDescriptor, isEmpty, isNone, alias, expandProperties } from '@ember/-internals/metal';
import { assert, deprecate } from '@ember/debug';
/**
@module @ember/object
*/

function expandPropertiesToArray(predicateName, properties) {
  let expandedProperties = [];

  function extractProperty(entry) {
    expandedProperties.push(entry);
  }

  for (let i = 0; i < properties.length; i++) {
    let property = properties[i];
    assert(`Dependent keys passed to \`${predicateName}\` computed macro can't have spaces.`, property.indexOf(' ') < 0);
    expandProperties(property, extractProperty);
  }

  return expandedProperties;
}

function generateComputedWithPredicate(name, predicate) {
  return (...properties) => {
    assert(`You attempted to use @${name} as a decorator directly, but it requires at least one dependent key parameter`, !isElementDescriptor(properties));
    let dependentKeys = expandPropertiesToArray(name, properties);
    let computedFunc = computed(...dependentKeys, function () {
      let lastIdx = dependentKeys.length - 1;

      for (let i = 0; i < lastIdx; i++) {
        let value = get(this, dependentKeys[i]);

        if (!predicate(value)) {
          return value;
        }
      }

      return get(this, dependentKeys[lastIdx]);
    });
    return computedFunc;
  };
}
/**
  A computed property macro that returns true if the value of the dependent
  property is null, an empty string, empty array, or empty function.

  Example:

  ```javascript
  import { set } from '@ember/object';
  import { empty } from '@ember/object/computed';

  class ToDoList {
    constructor(todos) {
      set(this, 'todos', todos);
    }

    @empty('todos') isDone;
  }

  let todoList = new ToDoList(
    ['Unit Test', 'Documentation', 'Release']
  );

  todoList.isDone; // false
  set(todoList, 'todos', []);
  todoList.isDone; // true
  ```

  Classic Class Example:

  ```javascript
  import EmberObject, { set } from '@ember/object';
  import { empty } from '@ember/object/computed';

  let ToDoList = EmberObject.extend({
    isDone: empty('todos')
  });

  let todoList = ToDoList.create({
    todos: ['Unit Test', 'Documentation', 'Release']
  });

  todoList.isDone; // false
  set(todoList, 'todos', []);
  todoList.isDone; // true
  ```

  @since 1.6.0
  @method empty
  @static
  @for @ember/object/computed
  @param {String} dependentKey
  @return {ComputedProperty} computed property which returns true if the value
  of the dependent property is null, an empty string, empty array, or empty
  function and false if the underlying value is not empty.

  @public
*/


export function empty(dependentKey) {
  assert('You attempted to use @empty as a decorator directly, but it requires a `dependentKey` parameter', !isElementDescriptor(Array.prototype.slice.call(arguments)));
  return computed(`${dependentKey}.length`, function () {
    return isEmpty(get(this, dependentKey));
  });
}
/**
  A computed property that returns true if the value of the dependent property
  is NOT null, an empty string, empty array, or empty function.

  Example:

  ```javascript
  import { set } from '@ember/object';
  import { notEmpty } from '@ember/object/computed';

  class Hamster {
    constructor(backpack) {
      set(this, 'backpack', backpack);
    }

    @notEmpty('backpack') hasStuff
  }

  let hamster = new Hamster(
    ['Food', 'Sleeping Bag', 'Tent']
  );

  hamster.hasStuff; // true
  set(hamster, 'backpack', []);
  hamster.hasStuff; // false
  ```

  Classic Class Example:

  ```javascript
  import EmberObject, { set } from '@ember/object';
  import { notEmpty } from '@ember/object/computed';

  let Hamster = EmberObject.extend({
    hasStuff: notEmpty('backpack')
  });

  let hamster = Hamster.create({
    backpack: ['Food', 'Sleeping Bag', 'Tent']
  });

  hamster.hasStuff; // true
  set(hamster, 'backpack', []);
  hamster.hasStuff; // false
  ```

  @method notEmpty
  @static
  @for @ember/object/computed
  @param {String} dependentKey
  @return {ComputedProperty} computed property which returns true if original
  value for property is not empty.
  @public
*/

export function notEmpty(dependentKey) {
  assert('You attempted to use @notEmpty as a decorator directly, but it requires a `dependentKey` parameter', !isElementDescriptor(Array.prototype.slice.call(arguments)));
  return computed(`${dependentKey}.length`, function () {
    return !isEmpty(get(this, dependentKey));
  });
}
/**
  A computed property that returns true if the value of the dependent property
  is null or undefined. This avoids errors from JSLint complaining about use of
  ==, which can be technically confusing.

  ```javascript
  import { set } from '@ember/object';
  import { none } from '@ember/object/computed';

  class Hamster {
    @none('food') isHungry;
  }

  let hamster = new Hamster();

  hamster.isHungry; // true

  set(hamster, 'food', 'Banana');
  hamster.isHungry; // false

  set(hamster, 'food', null);
  hamster.isHungry; // true
  ```

  Classic Class Example:

  ```javascript
  import EmberObject, { set } from '@ember/object';
  import { none } from '@ember/object/computed';

  let Hamster = EmberObject.extend({
    isHungry: none('food')
  });

  let hamster = Hamster.create();

  hamster.isHungry; // true

  set(hamster, 'food', 'Banana');
  hamster.isHungry; // false

  set(hamster, 'food', null);
  hamster.isHungry; // true
  ```

  @method none
  @static
  @for @ember/object/computed
  @param {String} dependentKey
  @return {ComputedProperty} computed property which returns true if original
  value for property is null or undefined.
  @public
*/

export function none(dependentKey) {
  assert('You attempted to use @none as a decorator directly, but it requires a `dependentKey` parameter', !isElementDescriptor(Array.prototype.slice.call(arguments)));
  return computed(dependentKey, function () {
    return isNone(get(this, dependentKey));
  });
}
/**
  A computed property that returns the inverse boolean value of the original
  value for the dependent property.

  Example:

  ```javascript
  import { set } from '@ember/object';
  import { not } from '@ember/object/computed';

  class User {
    loggedIn = false;

    @not('loggedIn') isAnonymous;
  }

  let user = new User();

  user.isAnonymous; // true
  set(user, 'loggedIn', true);
  user.isAnonymous; // false
  ```

  Classic Class Example:

  ```javascript
  import EmberObject, { set } from '@ember/object';
  import { not } from '@ember/object/computed';

  let User = EmberObject.extend({
    loggedIn: false,

    isAnonymous: not('loggedIn')
  });

  let user = User.create();

  user.isAnonymous; // true
  set(user, 'loggedIn', true);
  user.isAnonymous; // false
  ```

  @method not
  @static
  @for @ember/object/computed
  @param {String} dependentKey
  @return {ComputedProperty} computed property which returns inverse of the
  original value for property
  @public
*/

export function not(dependentKey) {
  assert('You attempted to use @not as a decorator directly, but it requires a `dependentKey` parameter', !isElementDescriptor(Array.prototype.slice.call(arguments)));
  return computed(dependentKey, function () {
    return !get(this, dependentKey);
  });
}
/**
  A computed property that converts the provided dependent property into a
  boolean value.

  Example:

  ```javascript
  import { set } from '@ember/object';
  import { bool } from '@ember/object/computed';


  class Hamster {
    @bool('numBananas') hasBananas
  }

  let hamster = new Hamster();

  hamster.hasBananas; // false

  set(hamster, 'numBananas', 0);
  hamster.hasBananas; // false

  set(hamster, 'numBananas', 1);
  hamster.hasBananas; // true

  set(hamster, 'numBananas', null);
  hamster.hasBananas; // false
  ```

  Classic Class Example:

  ```javascript
  import EmberObject, { set } from '@ember/object';
  import { bool } from '@ember/object/computed';


  let Hamster = EmberObject.extend({
    hasBananas: bool('numBananas')
  });

  let hamster = Hamster.create();

  hamster.hasBananas; // false

  set(hamster, 'numBananas', 0);
  hamster.hasBananas; // false

  set(hamster, 'numBananas', 1);
  hamster.hasBananas; // true

  set(hamster, 'numBananas', null);
  hamster.hasBananas; // false
  ```

  @method bool
  @static
  @for @ember/object/computed
  @param {String} dependentKey
  @return {ComputedProperty} computed property which converts to boolean the
  original value for property
  @public
*/

export function bool(dependentKey) {
  assert('You attempted to use @bool as a decorator directly, but it requires a `dependentKey` parameter', !isElementDescriptor(Array.prototype.slice.call(arguments)));
  return computed(dependentKey, function () {
    return Boolean(get(this, dependentKey));
  });
}
/**
  A computed property which matches the original value for the dependent
  property against a given RegExp, returning `true` if the value matches the
  RegExp and `false` if it does not.

  Example:

  ```javascript
  import { set } from '@ember/object';
  import { match } from '@ember/object/computed';

  class User {
    @match('email', /^.+@.+\..+$/) hasValidEmail;
  }

  let user = new User();

  user.hasValidEmail; // false

  set(user, 'email', '');
  user.hasValidEmail; // false

  set(user, 'email', 'ember_hamster@example.com');
  user.hasValidEmail; // true
  ```

  Classic Class Example:

  ```javascript
  import EmberObject, { set } from '@ember/object';
  import { match } from '@ember/object/computed';

  let User = EmberObject.extend({
    hasValidEmail: match('email', /^.+@.+\..+$/)
  });

  let user = User.create();

  user.hasValidEmail; // false

  set(user, 'email', '');
  user.hasValidEmail; // false

  set(user, 'email', 'ember_hamster@example.com');
  user.hasValidEmail; // true
  ```

  @method match
  @static
  @for @ember/object/computed
  @param {String} dependentKey
  @param {RegExp} regexp
  @return {ComputedProperty} computed property which match the original value
  for property against a given RegExp
  @public
*/

export function match(dependentKey, regexp) {
  assert('You attempted to use @match as a decorator directly, but it requires `dependentKey` and `regexp` parameters', !isElementDescriptor(Array.prototype.slice.call(arguments)));
  return computed(dependentKey, function () {
    let value = get(this, dependentKey);
    return regexp.test(value);
  });
}
/**
  A computed property that returns true if the provided dependent property is
  equal to the given value.

  Example:

  ```javascript
  import { set } from '@ember/object';
  import { equal } from '@ember/object/computed';

  class Hamster {
    @equal('percentCarrotsEaten', 100) satisfied;
  }

  let hamster = new Hamster();

  hamster.satisfied; // false

  set(hamster, 'percentCarrotsEaten', 100);
  hamster.satisfied; // true

  set(hamster, 'percentCarrotsEaten', 50);
  hamster.satisfied; // false
  ```

  Classic Class Example:

  ```javascript
  import EmberObject, { set } from '@ember/object';
  import { equal } from '@ember/object/computed';

  let Hamster = EmberObject.extend({
    satisfied: equal('percentCarrotsEaten', 100)
  });

  let hamster = Hamster.create();

  hamster.satisfied; // false

  set(hamster, 'percentCarrotsEaten', 100);
  hamster.satisfied; // true

  set(hamster, 'percentCarrotsEaten', 50);
  hamster.satisfied; // false
  ```

  @method equal
  @static
  @for @ember/object/computed
  @param {String} dependentKey
  @param {String|Number|Object} value
  @return {ComputedProperty} computed property which returns true if the
  original value for property is equal to the given value.
  @public
*/

export function equal(dependentKey, value) {
  assert('You attempted to use @equal as a decorator directly, but it requires `dependentKey` and `value` parameter', !isElementDescriptor(Array.prototype.slice.call(arguments)));
  return computed(dependentKey, function () {
    return get(this, dependentKey) === value;
  });
}
/**
  A computed property that returns true if the provided dependent property is
  greater than the provided value.

  Example:

  ```javascript
  import { set } from '@ember/object';
  import { gt } from '@ember/object/computed';

  class Hamster {
    @gt('numBananas', 10) hasTooManyBananas;
  }

  let hamster = new Hamster();

  hamster.hasTooManyBananas; // false

  set(hamster, 'numBananas', 3);
  hamster.hasTooManyBananas; // false

  set(hamster, 'numBananas', 11);
  hamster.hasTooManyBananas; // true
  ```

  Classic Class Example:

  ```javascript
  import EmberObject, { set } from '@ember/object';
  import { gt } from '@ember/object/computed';

  let Hamster = EmberObject.extend({
    hasTooManyBananas: gt('numBananas', 10)
  });

  let hamster = Hamster.create();

  hamster.hasTooManyBananas; // false

  set(hamster, 'numBananas', 3);
  hamster.hasTooManyBananas; // false

  set(hamster, 'numBananas', 11);
  hamster.hasTooManyBananas; // true
  ```

  @method gt
  @static
  @for @ember/object/computed
  @param {String} dependentKey
  @param {Number} value
  @return {ComputedProperty} computed property which returns true if the
  original value for property is greater than given value.
  @public
*/

export function gt(dependentKey, value) {
  assert('You attempted to use @gt as a decorator directly, but it requires `dependentKey` and `value` parameters', !isElementDescriptor(Array.prototype.slice.call(arguments)));
  return computed(dependentKey, function () {
    return get(this, dependentKey) > value;
  });
}
/**
  A computed property that returns true if the provided dependent property is
  greater than or equal to the provided value.

  Example:

  ```javascript
  import { set } from '@ember/object';
  import { gte } from '@ember/object/computed';

  class Hamster {
    @gte('numBananas', 10) hasTooManyBananas;
  }

  let hamster = new Hamster();

  hamster.hasTooManyBananas; // false

  set(hamster, 'numBananas', 3);
  hamster.hasTooManyBananas; // false

  set(hamster, 'numBananas', 10);
  hamster.hasTooManyBananas; // true
  ```

  Classic Class Example:

  ```javascript
  import EmberObject, { set } from '@ember/object';
  import { gte } from '@ember/object/computed';

  let Hamster = EmberObject.extend({
    hasTooManyBananas: gte('numBananas', 10)
  });

  let hamster = Hamster.create();

  hamster.hasTooManyBananas; // false

  set(hamster, 'numBananas', 3);
  hamster.hasTooManyBananas; // false

  set(hamster, 'numBananas', 10);
  hamster.hasTooManyBananas; // true
  ```

  @method gte
  @static
  @for @ember/object/computed
  @param {String} dependentKey
  @param {Number} value
  @return {ComputedProperty} computed property which returns true if the
  original value for property is greater or equal then given value.
  @public
*/

export function gte(dependentKey, value) {
  assert('You attempted to use @gte as a decorator directly, but it requires `dependentKey` and `value` parameters', !isElementDescriptor(Array.prototype.slice.call(arguments)));
  return computed(dependentKey, function () {
    return get(this, dependentKey) >= value;
  });
}
/**
  A computed property that returns true if the provided dependent property is
  less than the provided value.

  Example:

  ```javascript
  import { set } from '@ember/object';
  import { lt } from '@ember/object/computed';

  class Hamster {
    @lt('numBananas', 3) needsMoreBananas;
  }

  let hamster = new Hamster();

  hamster.needsMoreBananas; // true

  set(hamster, 'numBananas', 3);
  hamster.needsMoreBananas; // false

  set(hamster, 'numBananas', 2);
  hamster.needsMoreBananas; // true
  ```

  Classic Class Example:

  ```javascript
  import EmberObject, { set } from '@ember/object';
  import { lt } from '@ember/object/computed';

  let Hamster = EmberObject.extend({
    needsMoreBananas: lt('numBananas', 3)
  });

  let hamster = Hamster.create();

  hamster.needsMoreBananas; // true

  set(hamster, 'numBananas', 3);
  hamster.needsMoreBananas; // false

  set(hamster, 'numBananas', 2);
  hamster.needsMoreBananas; // true
  ```

  @method lt
  @static
  @for @ember/object/computed
  @param {String} dependentKey
  @param {Number} value
  @return {ComputedProperty} computed property which returns true if the
  original value for property is less then given value.
  @public
*/

export function lt(dependentKey, value) {
  assert('You attempted to use @lt as a decorator directly, but it requires `dependentKey` and `value` parameters', !isElementDescriptor(Array.prototype.slice.call(arguments)));
  return computed(dependentKey, function () {
    return get(this, dependentKey) < value;
  });
}
/**
  A computed property that returns true if the provided dependent property is
  less than or equal to the provided value.

  Example:

  ```javascript
  import { set } from '@ember/object';
  import { lte } from '@ember/object/computed';

  class Hamster {
    @lte('numBananas', 3) needsMoreBananas;
  }

  let hamster = new Hamster();

  hamster.needsMoreBananas; // true

  set(hamster, 'numBananas', 5);
  hamster.needsMoreBananas; // false

  set(hamster, 'numBananas', 3);
  hamster.needsMoreBananas; // true
  ```

  Classic Class Example:

  ```javascript
  import EmberObject, { set } from '@ember/object';
  import { lte } from '@ember/object/computed';

  let Hamster = EmberObject.extend({
    needsMoreBananas: lte('numBananas', 3)
  });

  let hamster = Hamster.create();

  hamster.needsMoreBananas; // true

  set(hamster, 'numBananas', 5);
  hamster.needsMoreBananas; // false

  set(hamster, 'numBananas', 3);
  hamster.needsMoreBananas; // true
  ```

  @method lte
  @static
  @for @ember/object/computed
  @param {String} dependentKey
  @param {Number} value
  @return {ComputedProperty} computed property which returns true if the
  original value for property is less or equal than given value.
  @public
*/

export function lte(dependentKey, value) {
  assert('You attempted to use @lte as a decorator directly, but it requires `dependentKey` and `value` parameters', !isElementDescriptor(Array.prototype.slice.call(arguments)));
  return computed(dependentKey, function () {
    return get(this, dependentKey) <= value;
  });
}
/**
  A computed property that performs a logical `and` on the original values for
  the provided dependent properties.

  You may pass in more than two properties and even use property brace
  expansion.  The computed property will return the first falsy value or last
  truthy value just like JavaScript's `&&` operator.

  Example:

  ```javascript
  import { set } from '@ember/object';
  import { and } from '@ember/object/computed';

  class Hamster {
    @and('hasTent', 'hasBackpack') readyForCamp;
    @and('hasWalkingStick', 'hasBackpack') readyForHike;
  }

  let tomster = new Hamster();

  tomster.readyForCamp; // false

  set(tomster, 'hasTent', true);
  tomster.readyForCamp; // false

  set(tomster, 'hasBackpack', true);
  tomster.readyForCamp; // true

  set(tomster, 'hasBackpack', 'Yes');
  tomster.readyForCamp; // 'Yes'

  set(tomster, 'hasWalkingStick', null);
  tomster.readyForHike; // null
  ```

  Classic Class Example:

  ```javascript
  import EmberObject, { set } from '@ember/object';
  import { and } from '@ember/object/computed';

  let Hamster = EmberObject.extend({
    readyForCamp: and('hasTent', 'hasBackpack'),
    readyForHike: and('hasWalkingStick', 'hasBackpack')
  });

  let tomster = Hamster.create();

  tomster.readyForCamp; // false

  set(tomster, 'hasTent', true);
  tomster.readyForCamp; // false

  set(tomster, 'hasBackpack', true);
  tomster.readyForCamp; // true

  set(tomster, 'hasBackpack', 'Yes');
  tomster.readyForCamp; // 'Yes'

  set(tomster, 'hasWalkingStick', null);
  tomster.readyForHike; // null
  ```

  @method and
  @static
  @for @ember/object/computed
  @param {String} dependentKey*
  @return {ComputedProperty} computed property which performs a logical `and` on
  the values of all the original values for properties.
  @public
*/

export const and = generateComputedWithPredicate('and', value => value);
/**
  A computed property which performs a logical `or` on the original values for
  the provided dependent properties.

  You may pass in more than two properties and even use property brace
  expansion.  The computed property will return the first truthy value or last
  falsy value just like JavaScript's `||` operator.

  Example:

  ```javascript
  import { set } from '@ember/object';
  import { or } from '@ember/object/computed';

  class Hamster {
    @or('hasJacket', 'hasUmbrella') readyForRain;
    @or('hasSunscreen', 'hasUmbrella') readyForBeach;
  }

  let tomster = new Hamster();

  tomster.readyForRain; // undefined

  set(tomster, 'hasUmbrella', true);
  tomster.readyForRain; // true

  set(tomster, 'hasJacket', 'Yes');
  tomster.readyForRain; // 'Yes'

  set(tomster, 'hasSunscreen', 'Check');
  tomster.readyForBeach; // 'Check'
  ```

  Classic Class Example:

  ```javascript
  import EmberObject, { set } from '@ember/object';
  import { or } from '@ember/object/computed';

  let Hamster = EmberObject.extend({
    readyForRain: or('hasJacket', 'hasUmbrella'),
    readyForBeach: or('hasSunscreen', 'hasUmbrella')
  });

  let tomster = Hamster.create();

  tomster.readyForRain; // undefined

  set(tomster, 'hasUmbrella', true);
  tomster.readyForRain; // true

  set(tomster, 'hasJacket', 'Yes');
  tomster.readyForRain; // 'Yes'

  set(tomster, 'hasSunscreen', 'Check');
  tomster.readyForBeach; // 'Check'
  ```

  @method or
  @static
  @for @ember/object/computed
  @param {String} dependentKey*
  @return {ComputedProperty} computed property which performs a logical `or` on
  the values of all the original values for properties.
  @public
*/

export const or = generateComputedWithPredicate('or', value => !value);
/**
  Creates a new property that is an alias for another property on an object.
  Calls to `get` or `set` this property behave as though they were called on the
  original property.

  Example:

  ```javascript
  import { set } from '@ember/object';
  import { alias } from '@ember/object/computed';

  class Person {
    name = 'Alex Matchneer';

    @alias('name') nomen;
  }

  let alex = new Person();

  alex.nomen; // 'Alex Matchneer'
  alex.name;  // 'Alex Matchneer'

  set(alex, 'nomen', '@machty');
  alex.name;  // '@machty'
  ```

  Classic Class Example:

  ```javascript
  import EmberObject, { set } from '@ember/object';
  import { alias } from '@ember/object/computed';

  let Person = EmberObject.extend({
    name: 'Alex Matchneer',

    nomen: alias('name')
  });

  let alex = Person.create();

  alex.nomen; // 'Alex Matchneer'
  alex.name;  // 'Alex Matchneer'

  set(alex, 'nomen', '@machty');
  alex.name;  // '@machty'
  ```

  @method alias
  @static
  @for @ember/object/computed
  @param {String} dependentKey
  @return {ComputedProperty} computed property which creates an alias to the
  original value for property.
  @public
*/

/**
  Where the `alias` computed macro aliases `get` and `set`, and allows for
  bidirectional data flow, the `oneWay` computed macro only provides an aliased
  `get`. The `set` will not mutate the upstream property, rather causes the
  current property to become the value set. This causes the downstream property
  to permanently diverge from the upstream property.

  Example:

  ```javascript
  import { set } from '@ember/object';
  import { oneWay }from '@ember/object/computed';

  class User {
    constructor(firstName, lastName) {
      set(this, 'firstName', firstName);
      set(this, 'lastName', lastName);
    }

    @oneWay('firstName') nickName;
  }

  let teddy = new User('Teddy', 'Zeenny');

  teddy.nickName; // 'Teddy'

  set(teddy, 'nickName', 'TeddyBear');
  teddy.firstName; // 'Teddy'
  teddy.nickName; // 'TeddyBear'
  ```

  Classic Class Example:

  ```javascript
  import EmberObject, { set } from '@ember/object';
  import { oneWay } from '@ember/object/computed';

  let User = EmberObject.extend({
    firstName: null,
    lastName: null,

    nickName: oneWay('firstName')
  });

  let teddy = User.create({
    firstName: 'Teddy',
    lastName: 'Zeenny'
  });

  teddy.nickName; // 'Teddy'

  set(teddy, 'nickName', 'TeddyBear'); // 'TeddyBear'
  teddy.firstName; // 'Teddy'
  teddy.nickName; // 'TeddyBear'
  ```

  @method oneWay
  @static
  @for @ember/object/computed
  @param {String} dependentKey
  @return {ComputedProperty} computed property which creates a one way computed
  property to the original value for property.
  @public
*/

export function oneWay(dependentKey) {
  assert('You attempted to use @oneWay as a decorator directly, but it requires a `dependentKey` parameter', !isElementDescriptor(Array.prototype.slice.call(arguments)));
  return alias(dependentKey).oneWay();
}
/**
  This is a more semantically meaningful alias of the `oneWay` computed macro,
  whose name is somewhat ambiguous as to which direction the data flows.

  @method reads
  @static
  @for @ember/object/computed
  @param {String} dependentKey
  @return {ComputedProperty} computed property which creates a one way computed
    property to the original value for property.
  @public
 */

/**
  Where `oneWay` computed macro provides oneWay bindings, the `readOnly`
  computed macro provides a readOnly one way binding. Very often when using
  the `oneWay` macro one does not also want changes to propagate back up, as
  they will replace the value.

  This prevents the reverse flow, and also throws an exception when it occurs.

  Example:

  ```javascript
  import { set } from '@ember/object';
  import { readOnly } from '@ember/object/computed';

  class User {
    constructor(firstName, lastName) {
      set(this, 'firstName', firstName);
      set(this, 'lastName', lastName);
    }

    @readOnly('firstName') nickName;
  });

  let teddy = new User('Teddy', 'Zeenny');

  teddy.nickName; // 'Teddy'

  set(teddy, 'nickName', 'TeddyBear'); // throws Exception
  // throw new EmberError('Cannot Set: nickName on: <User:ember27288>' );`

  teddy.firstName; // 'Teddy'
  ```

  Classic Class Example:

  ```javascript
  import EmberObject, { set } from '@ember/object';
  import { readOnly } from '@ember/object/computed';

  let User = EmberObject.extend({
    firstName: null,
    lastName: null,

    nickName: readOnly('firstName')
  });

  let teddy = User.create({
    firstName: 'Teddy',
    lastName:  'Zeenny'
  });

  teddy.nickName; // 'Teddy'

  set(teddy, 'nickName', 'TeddyBear'); // throws Exception
  // throw new EmberError('Cannot Set: nickName on: <User:ember27288>' );`

  teddy.firstName; // 'Teddy'
  ```

  @method readOnly
  @static
  @for @ember/object/computed
  @param {String} dependentKey
  @return {ComputedProperty} computed property which creates a one way computed
  property to the original value for property.
  @since 1.5.0
  @public
*/

export function readOnly(dependentKey) {
  assert('You attempted to use @readOnly as a decorator directly, but it requires a `dependentKey` parameter', !isElementDescriptor(Array.prototype.slice.call(arguments)));
  return alias(dependentKey).readOnly();
}
/**
  Creates a new property that is an alias for another property on an object.
  Calls to `get` or `set` this property behave as though they were called on the
  original property, but also print a deprecation warning.

  Example:

  ```javascript
  import { set } from '@ember/object';
  import { deprecatingAlias } from '@ember/object/computed';

  class Hamster {
    @deprecatingAlias('cavendishCount', {
      id: 'hamster.deprecate-banana',
      until: '3.0.0'
    })
    bananaCount;
  }

  let hamster = new Hamster();

  set(hamster, 'bananaCount', 5); // Prints a deprecation warning.
  hamster.cavendishCount; // 5
  ```

  Classic Class Example:

  ```javascript
  import EmberObject, { set } from '@ember/object';
  import { deprecatingAlias } from '@ember/object/computed';

  let Hamster = EmberObject.extend({
    bananaCount: deprecatingAlias('cavendishCount', {
      id: 'hamster.deprecate-banana',
      until: '3.0.0'
    })
  });

  let hamster = Hamster.create();

  set(hamster, 'bananaCount', 5); // Prints a deprecation warning.
  hamster.cavendishCount; // 5
  ```

  @method deprecatingAlias
  @static
  @for @ember/object/computed
  @param {String} dependentKey
  @param {Object} options Options for `deprecate`.
  @return {ComputedProperty} computed property which creates an alias with a
  deprecation to the original value for property.
  @since 1.7.0
  @public
*/

export function deprecatingAlias(dependentKey, options) {
  assert('You attempted to use @deprecatingAlias as a decorator directly, but it requires `dependentKey` and `options` parameters', !isElementDescriptor(Array.prototype.slice.call(arguments)));
  return computed(dependentKey, {
    get(key) {
      deprecate(`Usage of \`${key}\` is deprecated, use \`${dependentKey}\` instead.`, false, options);
      return get(this, dependentKey);
    },

    set(key, value) {
      deprecate(`Usage of \`${key}\` is deprecated, use \`${dependentKey}\` instead.`, false, options);
      set(this, dependentKey, value);
      return value;
    }

  });
}