Getters and setters in TypeScript classes

Getters and setters

Accessors look like properties to the caller but run code on get/set:

class Temperature {
  private _celsius: number;

  constructor(celsius: number) {
    this._celsius = celsius;
  }

  get celsius(): number {
    return this._celsius;
  }

  set celsius(value: number) {
    if (value < -273.15) throw new Error("Below absolute zero");
    this._celsius = value;
  }

  get fahrenheit(): number {
    return this._celsius * 9/5 + 32;
  }
}

const t = new Temperature(100);
console.log(t.fahrenheit); // 212 — no () needed
t.celsius = -300;          // throws

When to use accessors

Use a getter when you want a computed read-only value to look like a property. Use a setter when you need validation, transformation, or side effects on write. Do not add getters/setters just to wrap every private field — it adds noise without benefit if there is no logic involved.