<pre class="shiki github-dark shaku"><code>/** * @param {any} input * @return {(observable: Observable) =&gt; Observable} * returns a function which trasnform Observable */function map(transform) { return (source) =&gt; { return new Observable((subscriber) =&gt; { const originalNext = subscriber.next; subscriber.next = (value) =&gt; { const newValue = transform(value); originalNext.call(subscriber, newValue); }; source.subscribe(subscriber); }); }}</code></pre>

This is my accepted solution

This is a follow-up on 57. create an Observable. There are a lot of operators for Observable, if we think of Observable as event stream, then modifyin…