Typescript decorator for a once ran function

once.ts

function once(target, propertyKey: string, descriptor: PropertyDescriptor) {
    let old = descriptor.value;
    let ran = false;
    descriptor.value = function () {
        if (!ran) {
            ran = true;
            old.call(this);
        }
    }
}

function memoize(target, propertyKey: string, descriptor: PropertyDescriptor) {
    let old = descriptor.value;
    let ran = false;
    let val = null;
    descriptor.value = function () {
        if (!ran) {
            ran = true;
            val = old.call(this);
        }
        return val;
    }
}

function init(func) {
    return function (target: any, propertyKey: string) {
        let val = null;
        let initializer = target[func];
        let ran = false;

        Object.defineProperty(target, propertyKey, {
            get: function () {
                if (!ran) {
                    ran = true;
                    initializer.call(this);
                }
                return val
            },
            set: function (newval) {
                val = newval
            },
            enumerable: true,
            configurable: true
        })
    }
}

class Tester {
    c = 1;

    @init('doInit')
    test = 12

    test2 = 14

    doInit() {
        console.log('runMeOnce');
    }

    get test2() {
        return 12;
    }

    @once
    runOnce() {
        console.log('hi ', this.c++)
    }

    @memoize
    getRandom() {
        return Math.random();
    }
}

let t = new Tester();
t.runOnce();
t.runOnce();

console.log(t.getRandom());
console.log(t.getRandom());

console.log(t.test)
console.log(t.test)