title: Can we add properties to immutable object in JavaScript?
body: <p>An object is like: </p>
  
  <pre><code>const obj = [{name: 'Alex', age: 20}, {name: 'James', age: 22}];
  </code></pre>
  
  <p>This obect is immutable from Immutable.js.</p>
  
  <p>Is it possible to add a new key for each object? example:</p>
  
  <pre><code>const obj = [{name: 'Alex', age: 20, city: 'New York'}, {name: 'James', age: 20, city: 'Rome'}];
  </code></pre>