freeCodeCamp/reset-an-inherited-constructor-property.english.md at 56ded4174c324a2bdd8d8ac276e01650f78d6751

Valeriy 79d9012432 fix(curriculum): quotes in tests (#18828 )

* fix(curriculum): tests quotes

* fix(curriculum): fill seed-teardown

* fix(curriculum): fix tests and remove unneeded seed-teardown

2018-10-20 23:32:47 +05:30

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id, title, challengeType

id	title	challengeType
587d7db1367417b2b2512b86	Reset an Inherited Constructor Property	1

Description

When an object inherits its prototype from another object, it also inherits the supertype's constructor property. Here's an example:

function Bird() { }
Bird.prototype = Object.create(Animal.prototype);
let duck = new Bird();
duck.constructor // function Animal(){...}

But duck and all instances of Bird should show that they were constructed by Bird and not Animal. To do so, you can manually set Bird's constructor property to the Bird object:

Bird.prototype.constructor = Bird;
duck.constructor // function Bird(){...}

Instructions

Fix the code so duck.constructor and beagle.constructor return their respective constructors.

Tests

tests:
  - text: <code>Bird.prototype</code> should be an instance of <code>Animal</code>.
    testString: assert(Animal.prototype.isPrototypeOf(Bird.prototype), '<code>Bird.prototype</code> should be an instance of <code>Animal</code>.');
  - text: <code>duck.constructor</code> should return <code>Bird</code>.
    testString: assert(duck.constructor === Bird, '<code>duck.constructor</code> should return <code>Bird</code>.');
  - text: <code>Dog.prototype</code> should be an instance of <code>Animal</code>.
    testString: assert(Animal.prototype.isPrototypeOf(Dog.prototype), '<code>Dog.prototype</code> should be an instance of <code>Animal</code>.');
  - text: <code>beagle.constructor</code> should return <code>Dog</code>.
    testString: assert(beagle.constructor === Dog, '<code>beagle.constructor</code> should return <code>Dog</code>.');

Challenge Seed

function Animal() { }
function Bird() { }
function Dog() { }

Bird.prototype = Object.create(Animal.prototype);
Dog.prototype = Object.create(Animal.prototype);

// Add your code below this line



let duck = new Bird();
let beagle = new Dog();

Solution

function Animal() { }
function Bird() { }
function Dog() { }
Bird.prototype = Object.create(Animal.prototype);
Dog.prototype = Object.create(Animal.prototype);
Dog.prototype.constructor = Dog;
Bird.prototype.constructor = Bird;
let duck = new Bird();
let beagle = new Dog();

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