Error creating an instance

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The JavaScript language
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Class inheritance

Error creating an instance

importance: 5

Here’s the code with Rabbit extending Animal.

Unfortunately, Rabbit objects can’t be created. What’s wrong? Fix it.

class Animal {
 constructor(name) {
 this.name = name;
 }
}
class Rabbit extends Animal {
 constructor(name) {
 this.name = name;
 this.created = Date.now();
 }
}
let rabbit = new Rabbit("White Rabbit"); // Error: this is not defined
alert(rabbit.name);

That’s because the child constructor must call super().

Here’s the corrected code:

class Animal {
 constructor(name) {
 this.name = name;
 }
}
class Rabbit extends Animal {
 constructor(name) {
 super(name);
 this.created = Date.now();
 }
}
let rabbit = new Rabbit("White Rabbit"); // ok now
alert(rabbit.name); // White Rabbit