title: Array.filter() in Angular 2 Component
body: <p>In one component I can filter my array using the following:</p>
  
  <pre><code>// Array of product objects
  const result = products.filter(p =&gt; p.name.includes('val'));
  </code></pre>
  
  <p>and value of products remains same as the first value but filtered value stores in <code>result</code>.</p>
  
  <p>But in the following code, <code>filter()</code> filters array of strings itself:</p>
  
  <pre><code>// Array of strings
  const result = strs.filter(s =&gt; s.includes('val'));
  </code></pre>
  
  <p>The question is how can I filter strings and return result without modifying the <code>strs</code> itself?</p>
  
  <p><strong>Note:</strong> I tried with <code>array.filter(function() { return res; });</code> but didn't make any change.</p>