title: can not update state with immutability helper
body: <p>i have object in my state and nested object inside parent object, and updating objects in state may cause state mutating and lots of answers adviced to use immutability-helpers, (react-addons-update)
  this is my state: </p>
  
  <pre><code>    this.state = {
          room: {
              isOpen: false,
              index: '',
              roomNumber: '',
              reserved: '',
              isLux: null,
              _id: '',
              reserver:{
                 name: '',
                 surname: '',
                 national_id: '',
                 customer_number: '',
                 staying_til: '',
                 _id: ''
              }
  
          }
      }
  </code></pre>
  
  <p>and this is how update room properties:</p>
  
  <pre><code>roomChangeEvent(e){
         update(this.state, {
              room: {
                 [e.target.name]: {$set: e.target.value}
  
              }
         })
  }
  </code></pre>
  
  <p>and reserver properties</p>
  
  <pre><code>changeEvent(e){
          update(this.state, {
              room: {
                  reserver: {
                    [e.target.name]: {$set: e.target.value}
                  }
  
              }
         })
  }
  </code></pre>
  
  <p>but it is not updating state even though it is getting value and name. what is problem?</p>