private fields

private fields-1.js

class A {
	constructor() {
		console.log("A constructor is called");
	}
	// ---------------------------------------------
	#prop1;
	set prop1(val) {
		this.#prop1 = val;
	}
	get prop1() {
		return this.#prop1;
	}
	check1() {
		console.log("a2: " + this.#prop1);
	}
	// ---------------------------------------------
	#prop2;
	prop2 = {
		set(val) {this.#prop2 = val},
		get() {return this.#prop2},
	};
	check2() {
		console.log("a3: " + this.#prop2);
	}
	// ---------------------------------------------
	propEmpty;
}

class B extends A {}

let a, b;

// ==============================
console.log("CHECK prop1");
a = new B();
a.prop1 = 30;
console.log(a.prop1);
a.check1();

a.prop1 = 35;
console.log(a.prop1);
a.check1();

b = new B();
b.prop1 = 40;
console.log(b.prop1);
b.check1();

b = new B();
b.prop1 = 45;
console.log(b.prop1);
b.check1();

// ==============================
console.log("CHECK prop2");
a = new B();
a.prop2 = 50;
console.log(a.prop2);
a.check2();

a.prop2 = 55;
console.log(a.prop2);
a.check2();

// ==============================
console.log("a:", a);

// ==============================
console.log("CHECK propEmpty");
console.log("a.propEmpty:          ", a.propEmpty);
console.log("a.propEmpty == null:  ", a.propEmpty == null);
console.log("a.propEmpty == false: ", a.propEmpty == false);
console.log("a.propEmpty == '':    ", a.propEmpty == '');
console.log("a.propEmpty == 0:     ", a.propEmpty == 0);
console.log("a.propEmpty == {}:    ", a.propEmpty == {});

private fields-2.js

A = class {
	prop1 = {x: 10};
	prop2 = [1,2,3];
}

o1 = new A();
o2 = new A();

o1.prop1.x = 1000;
console.log("o1.prop1.x", o1.prop1.x);
console.log("o2.prop1.x", o2.prop1.x);

o2.prop2.push(4,5,6);
console.log("o1.prop2", o1.prop2);
console.log("o2.prop2", o2.prop2);

// =========================================================

B = class {
	#prop1 = 11;
	#prop2 = 22;
	#prop3 = 33;
	#prop4 = 44;
	constructor() {
		this.#prop1 = 55;
		this.#prop2 = 66;
	}
	getProp1() {
		console.log("(B) this.#prop1", this.#prop1);
	}
	getProp2() {
		console.log("(B) this.#prop2", this.#prop2);
	}
	getProp3() {
		console.log("(B) this.#prop3", this.#prop3);
	}
	getProp4() {
		console.log("(B) this.#prop4", this.#prop4);
	}
}

C = class extends B {
	#prop1 = 77;
	#prop2 = 88;
	#prop3 = 99;
	#prop4;
	constructor() {
		super();
		super.call(this);
		this.#prop1 = 11111;
	}
	getProp1() {
		console.log("(C) this.#prop1", this.#prop1);
	}
	getProp2() {
		console.log("(C) this.#prop2", this.#prop2);
	}
	getProp3() {
		console.log("(C) this.#prop3", this.#prop3);
	}
	getProp4() {
		console.log("(C) this.#prop4", this.#prop4);
	}
}

o1 = new B();
o1.getProp1();
o1.getProp2();
o1.getProp3();
o1.getProp4();

o2 = new C();
o2.getProp1();
o2.getProp2();
o2.getProp3();
o2.getProp4();

private fields-3.js

class a {
	static #_sp1 = 20;
	static set #sp1(v1) {this.#_sp1 = v1}
	static get #sp1() {return this.#_sp1}
	static #sm1() {this.#sp1 = 10; console.log(this.#sp1)}

	static _sp2 = 20;
	static set sp2(v2) {this._sp2 = v2}
	static get sp2() {return this._sp2}
	static sm2() {this.sp2 = 10; console.log(this.sp2)}

	#_ip1 = 10;
	set #ip1(v1) {this.#_ip1 = v1}
	get #ip1() {return this.#_ip1}
	#im1() {this.#ip1 = 10; console.log(this.#ip1)};

	_ip2 = 10;
	set ip2(v1) {this._ip2 = v1}
	get ip2() {return this._ip2}
	im2() {this.ip2 = 10; console.log(this.ip2)};

}

const i = new a ();