api.js

import base64 from 'react-native-base64';

...

const auth = base64.encode(`${Config.WP_USERNAME}:${Config.WP_PASSWORD}`);

export const updateData = async (route, data) => {
  try {
    fetch(Config.API_URL + route, {
      method: 'POST',
      headers: {
        Authorization: `Basic ${auth}`,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify(data),
    });
  } catch (error) {
    console.error(error);
  }
};