// @target: es2015 class A { get #fieldFunc() { return function() { this.x = 10; } } get #fieldFunc2() { return function(a, ...b) {}; } x = 1; test() { this.#fieldFunc(); const func = this.#fieldFunc; func(); new this.#fieldFunc(); const arr = [ 1, 2 ]; this.#fieldFunc2(0, ...arr, 3); const b = new this.#fieldFunc2(0, ...arr, 3); const str = this.#fieldFunc2`head${1}middle${2}tail`; this.getInstance().#fieldFunc2`test${1}and${2}`; } getInstance() { return new A(); } }