@lagrange/animator/src/utils/screen.js

This library helps making parallax animations on scroll. It is built with performance in mind, as it doesn't need to relayout or paint to operate.

import { SCREEN_TOP, SCREEN_CENTER, SCREEN_BOTTOM } from '../Constants';

export const screen = {};

export function updateScreen() {
	screen[SCREEN_TOP] = 0;
	screen[SCREEN_CENTER] = (window.innerHeight / 2);
	screen[SCREEN_BOTTOM] = window.innerHeight;
}

updateScreen();