React Native android release with scripts and fastlane

build-apk.sh

#!/usr/bin/env bash

ROOT="$(cd "$( dirname "${BASH_SOURCE[0]}" )/.." && pwd)"

main() {
  local mode="$1"
  echo "building apk with mode ${mode}"
  cd "${ROOT}"
  build_android "${mode}"
  print_usage "${mode}"
}

build_android() {
  local mode="$1"
  local gradleTask="assembleDebug"
  if [[ "${mode}" == "release" ]]; then
    gradleTask="assembleRelease"
  fi
  ( cd android && ./gradlew "${gradleTask}" )
}

print_usage() {
  local mode="$1"
  local output="${ROOT}/android/app/build/outputs/apk/app-${mode}.apk"
  echo "You can: adb install -r ${output}"
}

( main "$@" )

Fastfile

fastlane_version '2.64.1'

default_platform :android

platform :android do
  desc 'Deploy a new version to the Google Play'
  lane :alpha do
    gradle(task: 'assembleRelease')
    supply(
        track: 'alpha'
    )
  end
end

package.json

{
  "scripts": {
    "build:android:debug": "scripts/build-apk.sh debug",
    "build:android:release": "scripts/build-apk.sh release",
    "deploy:android:alpha": "cd android && bundle exec fastlane alpha"
  }
}