react-native-size-matters

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

Installation

npm install --save react-native-size-matters
//or:
yarn add react-native-size-matters

Motivation

When developing with react-native, you need to manually adjust your app to look great on variety of different screen sizes. That's a tedious job.
react-native-size-matters provides some simple tooling to make your scaling a whole lot easier.
The idea is to develop once on a standard ~5" screen mobile device and then simply apply the provided utils.
📖 You can read more about what led to this library on my blog post, that can be found in this repo or at Soluto Engineering Blog.

Api

Scaling Functions

import { scale, verticalScale, moderateScale } from 'react-native-size-matters';

const Component = props =>
    <View style={{
        width: scale(30),
        height: verticalScale(50),
        padding: moderateScale(5)
    }}/>;

• base screen size
  Guidline screen size is set to iPhone 6 screen size ( 375 x 667 ) but you can change them using "react-native-config" library by setting BASE_WIDTH and BASE_HEIGHT in the config file.

• resize mode Resize mode can be given in config file and can be one of the following values: ['contain', 'cover', 'width', 'height'], the default value is 'contain'

• scale(size: number)
  Will return linear scaled result of the provided size, based on your device's screen width.

• verticalScale(size: number)
  Will return linear scaled result of the provided size, based on your device's screen height.

• moderateScale(size: number, factor?: number)
  Sometimes you don't want to scale everything in a linear manner, that's where moderate scale comes in.
  The cool thing about it is that you can control the resize factor (default is 0.5).
  If normal scale will increase your size by +2X, moderateScale will only increase it by +X, for example:
  ➡️ scale(10) = 20
  ➡️ moderateScale(10) = 15
  ➡️ moderateScale(10, 0.1) = 11

ScaledSheet

import { ScaledSheet } from 'react-native-size-matters';

const styles = ScaledSheet.create(stylesObject)

ScaleSheet will take the same stylesObject a regular StyleSheet will take, plus a special (optional) annotation that will automatically apply the scale functions for you:

• <size>@s - will apply scale function on size.
• <size>@vs - will apply verticalScale function on size.
• <size>@ms - will apply moderateScale function with resize factor of 0.5 on size.
• <size>@ms<factor> - will apply moderateScale function with resize factor of factor on size.

Example:

import { ScaledSheet } from 'react-native-size-matters';

const styles = ScaledSheet.create({
    container: {
        width: '100@s', // = scale(100)
        height: '200@vs', // = verticalScale(200)
        margin: 5
    },
    row: {
        padding: '10@ms0.3', // = moderateScale(10, 0.3)
        height: '50@ms' // = moderateScale(50)
    }
});

Examples

You can clone the expo-example-app from this repo, run npm install and npm start and scan the presented QR code in the Expo app on your preferred device.
The app has a on/off switch for using react-native-size-matters, so you can test yourself how the app will look with and without scaling.
It is expected to look good on every device you want - iOS or Android, phone or tablet, basically anything (please let me know if not).
There are also some attached screenshots in the repo if you don't feel like cloning.