just another Cordova before_compile hook, to use app version from config.xml in your app

version.json

{
  "version" : {
    "MAJOR" : "0",
    "MINOR" : "1",
    "PATCH" : "0"
  }
}

version_bumper.py

#!/usr/bin/env python
import json
import xml.etree.ElementTree as ET

file_json = 'www/js/version.json'

if __name__ == "__main__":
  with open(file_json, 'r') as f:
    data = f.read()
    json_data = json.loads(data)
  f.closed

  with open('config.xml', 'r') as f:
    data = f.read()
    tree = ET.fromstring(data)
    xml_version = tree.get('version')
  f.closed

  xml_version_splitted = xml_version.split(".")

  json_version = json_data['version']
  if(xml_version_splitted[0] == json_version['MAJOR'] and xml_version_splitted[1] == json_version['MINOR'] and xml_version_splitted[2] == json_version['PATCH']):
    exit(0)
  else:
    print('new version detected in config.xml, updating ', file_json)
    json_data['version']['MAJOR'] = xml_version_splitted[0]
    json_data['version']['MINOR'] = xml_version_splitted[1]
    json_data['version']['PATCH'] = xml_version_splitted[2]
    with open(file_json, 'w') as of:
      json.dump(json_data, of)
    exit(0)