title: When to use const with objects in JavaScript?
body: <p>I recently read about ES6 <code>const</code> keyword and I can understand its importance when having something like this:</p>
  
  <pre><code>(function(){
      const PI = 3.14;
      PI = 3.15; //  Uncaught TypeError: Assignment to constant variable
  })();
  </code></pre>
  
  <p>So, nobody can change my <code>PI</code> variable.</p>
  
  <p>The misunderstanding I have is that I don't understand in which situation the use of <code>const</code> with objects can make sense (other than preventing people to do <code>myObj = newValue;</code>).</p>
  
  <pre><code>(function(){
      const obj = {a:1 ,b: 2, c:3};
      //obj = {x:7 , y:8, z: 9}
      //This is good
      //TypeError: Assignment to constant variable.
  
      obj.a=7; obj.b=8 ; obj.c=9;
      console.log(obj); //outputs: {a: 7, b: 8, c: 9}
  })();
  </code></pre>
  
  <p>So when declaring an object: when should I say: Now I <strong>must</strong> declare my object with <code>const</code>?</p>