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.
```js
var SpaceShuttle = function(targetPlanet){
this.targetPlanet = targetPlanet;
}
var zeus = new SpaceShuttle('Jupiter');
```
The class
syntax simply replaces the constructor function creation:
```js
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.SpaceShuttle
used above.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.
Vegetable
should be a class
with a defined constructor
method.
testString: assert(typeof Vegetable === 'function' && typeof Vegetable.constructor === 'function');
- text: class
keyword should be used.
testString: assert(code.match(/class/g));
- text: Vegetable
should be able to be instantiated.
testString: assert(() => {const a = new Vegetable("apple"); return typeof a === 'object';});
- text: carrot.name
should return carrot
.
testString: assert(carrot.name=='carrot');
```