react-native-size-matters/lib/extend/scaling-utils.extend.js

A React-Native utility belt for scaling the size your apps UI across different sized devices

import { Dimensions } from 'react-native';
import { SIZE_MATTERS_BASE_WIDTH, SIZE_MATTERS_BASE_HEIGHT } from '@env';

const { width, height } = Dimensions.get('window');
const [shortDimension, longDimension] = width < height ? [width, height] : [height, width];

//Default guideline sizes are based on standard ~5" screen mobile device
const guidelineBaseWidth = SIZE_MATTERS_BASE_WIDTH || 350;
const guidelineBaseHeight = SIZE_MATTERS_BASE_HEIGHT || 680;

export const scale = size => shortDimension / guidelineBaseWidth * size;
export const verticalScale = size => longDimension / guidelineBaseHeight * size;
export const moderateScale = (size, factor = 0.5) => size + (scale(size) - size) * factor;
export const moderateVerticalScale = (size, factor = 0.5) => size + (verticalScale(size) - size) * factor;

export const s = scale;
export const vs = verticalScale;
export const ms = moderateScale;
export const mvs = moderateVerticalScale;