Sum - Object Composition - Lab

function() {
        let firstElement;
        let secondElement;
        let result;

        return {
            init: (selector1, selector2, resultSelector) => {
                firstElement = document.querySelector(selector1);
                secondElement = document.querySelector(selector2);
                result = document.querySelector(resultSelector);
            },
            add: () => {
                result.value = Number(firstElement.value) + Number(secondElement.value);
            },
            subtract: () => {
                result.value = Number(firstElement.value) - Number(secondElement.value);

            }
        };
    }