Classes in JavaScript

Class syntax with inheritance and static members.

class Animal {
  constructor(name) {
    this.name = name;
  }

  speak() {
    return `${this.name} makes a sound`;
  }

  static create(name) {
    return new Animal(name);
  }
}

class Dog extends Animal {
  speak() {
    return `${super.speak()}: a woof`;
  }
}

How it works

1. constructor initializes instance fields.
2. extends and super build on a base class.
3. static methods belong to the class, not instances.

Keywords and builtins used here

• class
• constructor
• extends
• return
• static
• super
• this

The run, in numbers

Lines

19

Characters to type

233

Tokens

68

Three-star pace

95 tpm

At the three-star pace of 95 tokens a minute, this run takes about 43 seconds.

Type this snippet

Step 1 of 3 in Classes, step 35 of 43 in Language basics.

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