JSON stringify ES6 class property with getter/setter

Question

I have a JavaScript ES6 class that has a property set with set and accessed with get functions. It is also a constructor parameter so the class can

Answer 1

As mentioned by @Amadan you can write your own toJSON method.

Further more, in order to avoid re-updating your method every time you add a property to your class you can use a more generic toJSON implementation.

class MyClass {

  get prop1() {
    return 'hello';
  }
  
  get prop2() {
    return 'world';
  }

  toJSON() {

    // start with an empty object (see other alternatives below) 
    const jsonObj = {};

    // add all properties
    const proto = Object.getPrototypeOf(this);
    for (const key of Object.getOwnPropertyNames(proto)) {      
      const desc = Object.getOwnPropertyDescriptor(proto, key);
      const hasGetter = desc && typeof desc.get === 'function';
      if (hasGetter) {
        jsonObj[key] = desc.get();
      }
    }

    return jsonObj;
  }
}

const instance = new MyClass();
const json = JSON.stringify(instance);
console.log(json); // outputs: {"prop1":"hello","prop2":"world"}

If you want to emit all properties and all fields you can replace const jsonObj = {}; with

const jsonObj = Object.assign({}, this);

Alternatively, if you want to emit all properties and some specific fields you can replace it with

const jsonObj = {
    myField: myOtherField
};