Rocket.Chat.ReactNative/app/utils/scaling.js

import { Dimensions } from 'react-native';

import { isTablet } from './deviceInfo';

const { width, height } = Dimensions.get('window');

const guidelineBaseWidth = isTablet ? 600 : 375;
const guidelineBaseHeight = isTablet ? 800 : 667;

const scale = size => (width / guidelineBaseWidth) * size;
const verticalScale = size => (height / guidelineBaseHeight) * size;
const moderateScale = (size, factor = 0.5) => size + ((scale(size) - size) * factor);

export { scale, verticalScale, moderateScale };