title: Const value can be change
body: <p>I followed a tutorial on meteorjs here: 
  <a href="https://www.meteor.com/tutorials/react/forms-and-events" rel="nofollow noreferrer">https://www.meteor.com/tutorials/react/forms-and-events</a></p>
  
  <p>One of the code is using const. 
  <code>
  const text = ReactDOM.findDOMNode(this.refs.textInput).value.trim();</code></p>
  
  <p>As far as I know from my reading on SO website other site, <code>const</code> value can't be changed. However when I keyin any text in my application input box, there is no error thrown for reassigning <code>const</code> value.</p>
  
  <p>Why is this happening and did I understand <code>const</code> wrong? I hope someone can explain to me and thanks in advance.</p>
  
  <p>Example code:</p>
  
  <pre><code>import React, { Component, PropTypes } from 'react';
  import ReactDOM from 'react-dom';
  import { createContainer } from 'meteor/react-meteor-data';
  
  import { Tasks } from '../api/tasks.js';
  ...some lines skipped...
  
  // App component - represents the whole app
  class App extends Component {
    handleSubmit(event) {
      event.preventDefault();
  
      // Find the text field via the React ref
      const text = ReactDOM.findDOMNode(this.refs.textInput).value.trim();
  
      Tasks.insert({
        text,
        createdAt: new Date(), // current time
      });
  
      // Clear form
      ReactDOM.findDOMNode(this.refs.textInput).value = '';
    }
  
    renderTasks() {
      return this.props.tasks.map((task) =&gt; (
        &lt;Task key={task._id} task={task} /&gt;
  </code></pre>