2.4 KiB
id, title, challengeType, forumTopicId
id | title | challengeType | forumTopicId |
---|---|---|---|
587d7b8b367417b2b2512b53 | Use class Syntax to Define a Constructor Function | 1 | 301212 |
--description--
ES6 provides a new syntax to create objects, using the class keyword.
It should be noted that the class
syntax is just syntax, and not a full-fledged class-based implementation of an object-oriented paradigm, unlike in languages such as Java, Python, Ruby, etc.
In ES5, we usually define a constructor function and use the new
keyword to instantiate an object.
var SpaceShuttle = function(targetPlanet){
this.targetPlanet = targetPlanet;
}
var zeus = new SpaceShuttle('Jupiter');
The class
syntax simply replaces the constructor function creation:
class SpaceShuttle {
constructor(targetPlanet) {
this.targetPlanet = targetPlanet;
}
}
const zeus = new SpaceShuttle('Jupiter');
It should be noted that the class
keyword declares a new function, to which a constructor is added. This constructor is invoked when new
is called to create a new object.
Notes:
- UpperCamelCase should be used by convention for ES6 class names, as in
SpaceShuttle
used above. - The constructor method is a special method for creating and initializing an object created with a class. You will learn more about it in the Object Oriented Programming section of the JavaScript Algorithms And Data Structures Certification.
--instructions--
Use the class
keyword and write a constructor to create the Vegetable
class.
The Vegetable
class allows you to create a vegetable object with a property name
that gets passed to the constructor.
--hints--
Vegetable
should be a class
with a defined constructor
method.
assert(
typeof Vegetable === 'function' && typeof Vegetable.constructor === 'function'
);
class
keyword should be used.
assert(code.match(/class/g));
Vegetable
should be able to be instantiated.
assert(() => {
const a = new Vegetable('apple');
return typeof a === 'object';
});
carrot.name
should return carrot
.
assert(carrot.name == 'carrot');
--seed--
--seed-contents--
// Only change code below this line
// Only change code above this line
const carrot = new Vegetable('carrot');
console.log(carrot.name); // Should display 'carrot'
--solutions--
class Vegetable {
constructor(name) {
this.name = name;
}
}
const carrot = new Vegetable('carrot');