>GoJS</b> provides an <strong><a href="../samples/#extensions">extensions gallery</a></strong>,
  showcasing the creation of custom tools and layouts.
  Those classes and samples are written in TypeScript, available at <code>../extensionsJSM/</code>,
  as ECMAScript/JavaScript modules -- these use the <code>../release/go-module.js</code> library.
  We recommend that you copy the files that you need into your project, so that you can adjust how they refer to the GoJS library
  that you choose and so that you