title: What are the differences between `Map.clear()` vs `new Map()` in Javascript?
body: <p>Recently came across an issue with <code>mobx</code> where an <code>observable.map</code> does not react when modified its state with ES6 <code>Map.prototype.clear()</code>. However, when it's reassigned with <code>new Map()</code> it seems to work as expected. What could be the differences using those in Javascript?</p>