Instance Properties

Instance properties are properties that belong to each individual object created from a class. They are typically defined inside the constructor method, but can also be defined directly in the class body (public instance fields) as of ES2022.

Key Points

• Instance properties hold data specific to each instance.
• Can be initialized in the constructor or directly in the class body.
• Public fields are a newer syntax for defining instance properties outside the constructor.

Code Example

class Product {
  // Public instance field (ES2022)
  category = "general";

  constructor(name, price) {
    this.name = name; // instance property
    this.price = price; // instance property
  }

  display() {
    console.log(`${this.name} (${this.category}): ${this.price}`);
  }
}

const phone = new Product("Phone", 699);
phone.display(); // "Phone (general): 699"