build

#!/bin/bash
#
# See: https://google.github.io/styleguide/shell.xml
# See: https://github.com/google/closure-stylesheets
# See: https://developers.google.com/closure/compiler/

set -e

readonly CWD=$(cd $(dirname $0); pwd)
readonly LIB="${CWD}/lib"
readonly TMP="${CWD}/tmp"
readonly SRC="${CWD}/src"

readonly WGET="$(which wget)"
readonly CURL="$(which curl)"
readonly UNZIP="$(which unzip)"

readonly JAVA="$(which java)"
# Hot fix for clean installation of OS X El Capitan.
readonly JAVA_OSX="/Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home/bin/java"

# https://github.com/google/closure-compiler/wiki/Binary-Downloads
# readonly JS_COMPILER_ZIP="compiler-latest.zip"
readonly JS_COMPILER_ZIP="compiler-20200719.zip"
readonly JS_COMPILER_URL="https://dl.google.com/closure-compiler/${JS_COMPILER_ZIP}"
readonly JS_COMPILER_JAR="${LIB}/compiler.jar"
readonly NODE_MODULES="${CWD}/node_modules"

#
# Downloads closure compiler.
#
function download() {
  if [[ ! -f "${JS_COMPILER_JAR}" ]]; then
    cd "${TMP}"

    echo -n "Downloading closure compiler: "
    if [[ -n "$CURL" ]]; then
      $CURL --silent -L "${JS_COMPILER_URL}" > "${TMP}/${JS_COMPILER_ZIP}"
    else
      $WGET --quiet "${JS_COMPILER_URL}" -O "${TMP}/${JS_COMPILER_ZIP}"
    fi
    echo "Done"

    echo -n "Extracting closure compiler:  "
    $UNZIP -q "${TMP}/${JS_COMPILER_ZIP}" -d "${LIB}"
    if [[ ! -f "${JS_COMPILER_JAR}" ]]; then
      mv "${LIB}"/*compiler*.jar "${JS_COMPILER_JAR}"
    fi
    echo "Done"

    cd "${CWD}"
  fi
}

#
# Runs closure compiler.
#
function run_compiler() {
  echo -n "Running closure compiler:     "
  local JAVA_BIN="${JAVA}"
  if [[ -f "${JAVA_OSX}" ]]; then
    JAVA_BIN="${JAVA_OSX}"
  fi

  if [[ -d "${SRC}" ]]; then
    "${JAVA_BIN}" -jar "${JS_COMPILER_JAR}" \
      --js_output_file "/dev/null" \
      --entry_point "${CWD}/index.js" \
      --js "${NODE_MODULES}/**/package.json" \
      --js "${NODE_MODULES}/**/**.js" \
      --js "${CWD}/index.js" \
      --js "${CWD}/package.json" \
      --js "${SRC}/**/*.js" \
      --jscomp_warning lintChecks \
      --warning_level VERBOSE \
      --compilation_level ADVANCED \
      --use_types_for_optimization \
      --dependency_mode PRUNE \
      --language_out STABLE \
      --charset UTF-8 \
      --process_common_js_modules \
      --module_resolution NODE \
      --isolation_mode IIFE \
      --rewrite_polyfills false
  else
    echo -n "[WARN] Directory '${SRC}' doesn't exist. "
  fi

  echo "Done"
}

#
# The main function.
#
function main() {
  mkdir -p "${LIB}"
  mkdir -p "${TMP}"

  download
  run_compiler

  rm -rf "${TMP}"
  rm -rf "${LIB}"
}

main "$@"