factorcalc.js

/*******************************/
/* approach 1: structured data */
/*******************************/
function calc(state, x) {
    return calcSubPart(state, x-1) + calcSubPart(state, x-1);
}

function calcSubPart(state, y) {
    return state * y;
}

function test() {
    let state = { factor: 2 };
    let result = calc(state, 1);
}

/*******************/
/* approach 2: oop */
/*******************/
class factorCalc {
    constructor(factor) {
        this.factor = factor;
    }

    function calc(x) {
        return calcSubPart(x-1) + calcSubPart(x-1);
    }

    function calcSubPart(y) {
        return factor * y;
    }
}

function test() {
    let calculator = new FactorCalc(2);
    let result = calculator.calc(1);
}