title: spread operator vs array.concat()
body: <p>What is the difference between <code>spread operator</code> and <code>array.concat()</code></p>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>let parts = ['four', 'five'];
  let numbers = ['one', 'two', 'three'];
  console.log([...numbers, ...parts]);</code></pre>
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  </div>
  </p>
  <p><code>Array.concat()</code> function</p>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>let parts = ['four', 'five'];
  let numbers = ['one', 'two', 'three'];
  console.log(numbers.concat(parts));</code></pre>
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  </div>
  </p>
  <blockquote>
  <p>Both results are same. So, what kind of scenarios we want to use them? And which one is best for performance?</p>
  </blockquote>