How to use Rx.Observable.prototype.let operator?
<p>The example and explanation of the <code>let</code> operator (<a href="https://github.com/Reactive-Extensions/RxJS/blob/master/doc/api/core/operators/let.md">https://github.com/Reactive-Extensions/RxJS/blob/master/doc/api/core/operators/let.md</a>) is not clear. Anyone has a good example/explanation how the <code>let</code> operator works, and when we should use it?</p>