In general, you&#x27;re unlikely to need them.<p>Instead of cobbling together disparate libraries for a virtual dom (React), state (Redux), immutability (Immutable.js), and types (Flow &#x2F; TypeScript), the entire language and its core libraries are developed as a holistic (but still modular) unit. In this way, Elm is the BSD to JavaScript&#x27;s GNU&#x2F;Linux.<p>Strong typing and immutability are baked directly into the core language, elm-lang&#x2F;html includes an efficient Virtual DOM, and Redux-style action &#x2F; reducer cycles tend to naturally arise from &quot;The Elm Architecture,&quot; and don&#x27;t need significant support beyond what&#x27;s already in the core language.<p>If you&#x27;ve bought into the React&#x2F;Redux paradigm, it&#x27;s worth giving Elm a shot: the entire language and core libraries are intentionally designed to more cleanly, reliably, and maintainably implement the same structure.