build.xml

<?xml version="1.0" encoding="utf-8"?>
<project name="chronos">
  <target name="install" description="Install dependencies">
    <exec executable="npm" dir="${sourceDir}" failonerror="true">
      <arg value="install"/>
    </exec>
    <echo message="install project dependencies" />
  </target>
  <target name="eslint" description="Check source lint">
    <exec executable="npm" dir="${sourceDir}" failonerror="true">
      <arg value="run"/>
      <arg value="lint"/>
    </exec>
  </target>
  <target name="build" description="Generate assets">
    <delete includeemptydirs="true" failonerror="false">
      <fileset dir="${sourceDir}/build" includes="**/*"/>
    </delete>
    <exec executable="npm" dir="${sourceDir}" failonerror="true">
      <arg value="run"/>
      <arg value="build"/>
    </exec>
    <echo message="build project with npm" />
    <mkdir dir="${sourceDir}/build/assets" />
    <copy todir="${sourceDir}/build/assets">
      <fileset dir="${sourceDir}/assets" />
    </copy>
    <copy file="${sourceDir}/index.html" tofile="${sourceDir}/build/index.html"/>
  </target>

  <target name="assets.uptodate" depends="sourceDir.check" if="sourceDir.nochanges">
    <echo>${sourceDir} Hasn't been updated, skipping asset compilation.</echo>
  </target>

  <target name="sourceDir.check">
    <uptodate property="sourceDir.nochanges">
      <srcfiles dir="${sourceDir}" includes="**/*.js" />
      <srcfiles dir="${sourceDir}" includes="**/*.jsx" />
      <srcfiles dir="${sourceDir}" includes="**/*.css" />
      <mapper type="merge" to="${sourceDir}/build/assets/js/bundle.js" />
    </uptodate>
  </target>

  <target name="generateAssets" depends="assets.uptodate" unless="sourceDir.nochanges">
    <echo message="Building assets" />
    <antcall target="install">
    </antcall>
    <antcall target="build">
    </antcall>
  </target>
</project>