[рони]

Tipylja,
вариант...

const paralax = (() => {
const   bg = document.querySelector('.header__bg'),
        user = document.querySelector('.header__me'),
        text = document.querySelector('.header__img-portfolio'),
        move = (block, windowScroll, rateVaue) => {
            const shift = windowScroll / -rateVaue + '%';
            const style = block.style;
            style.top = shift;
        },
        init = (windowScroll) => {
            move(bg, windowScroll, 45);
        };

    return {
        move,
        init
    }

})();