How to export variables to separate file? React Native

Question

In my project I have main file with global styles but also I use styles in a individual components. Nonetheless I use the same variables to pass font-size, colours to elements.

I'm not an expert in React but I think that will be nice to move variables to separate file to don't repeat the code. How can I do this in a proper way?

Global styles:

'use strict';

  let React = require('react-native');

  let {
    StyleSheet,
  } = React;

  let INIT_COLOR = "#fff";
  let INIT_FONT_SIZE = 16; 


  module.exports = StyleSheet.create({
    container: {
        backgroundColor: INIT_COLOR,
        fontSize: INIT_FONT_SIZE
    },
});  

Component styles:

import React from 'react';
import { View, StyleSheet, Button} from 'react-native';

class ActionButton extends React.Component {

 render() {
   let INIT_COLOR = "#fff";
   let INIT_FONT_SIZE = 16;

  return (
    <View style={styles.buttonContainer}>
        <Button
          onPress={this.props.onPress}
        />
    </View>
   );
 }
}

const styles = StyleSheet.create({
    buttonContainer: {
      backgroundColor: INIT_COLOR,
      fontSize: INIT_FONT_SIZE
    }
   });

export default ActionButton;

Answer 1

You can just create a file into themes/variables.js for example. something like this:

export const colors = {
  INIT_COLOR: "#fff",
  //... more colors here
};

export const fonts = {
  INIT_FONT_SIZE: 16,
};

You can also export each individual color if you want, but I'd prefer to export an object of colors.

Then you can import that file in your components:

import React from 'react';
import { View, StyleSheet, Button} from 'react-native';
import { colors, fonts } from 'theme/variables';

class ActionButton extends React.Component {

 render() {
  return (
    <View style={styles.buttonContainer}>
        <Button
          onPress={this.props.onPress}
        />
    </View>
   );
 }
}

const styles = StyleSheet.create({
    buttonContainer: {
      backgroundColor: colors.INIT_COLOR,
      fontSize: fonts.INIT_FONT_SIZE
    }
});

export default ActionButton;