title: What is pipe() function in Angular
body: <p>Pipes are filters for transforming data (formats) in the template.</p>
  
  <p>I came across the <code>pipe()</code> function as below. What does this <code>pipe()</code> function exactly mean in this case? </p>
  
  <pre><code>return this.http.get&lt;Hero&gt;(url)
    .pipe(
      tap(_ =&gt; this.log(`fetched hero id=${id}`)),
      catchError(this.handleError&lt;Hero&gt;(`getHero id=${id}`))
  );
  </code></pre>