build.gradle

// Top-level build file where you can add configuration options common to all sub-projects/modules.
import groovy.json.JsonSlurper

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.2.3'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        mavenLocal()
        jcenter()
        maven {
            // All of React Native (JS, Obj-C sources, Android binaries) is installed from npm
            url "$rootDir/../node_modules/react-native/android"
        }
    }
}

subprojects {
    ext {
        def npmVersion = getNpmVersionArray()
        versionMajor = npmVersion[0]
        versionMinor = npmVersion[1]
        versionPatch = npmVersion[2]
    }
}

def getNpmVersion() {
    def inputFile = new File("../package.json")
    def packageJson = new JsonSlurper().parseText(inputFile.text)
    return packageJson["version"]
}

def getNpmVersionArray() { // major [0], minor [1], patch [2]
    def (major, minor, patch) = getNpmVersion().tokenize('.')
    return [Integer.parseInt(major), Integer.parseInt(minor), Integer.parseInt(patch)] as int[]
}