title: how to create state array in react js
body: <p>I'm creating a simple to-do app where the user can select the date, write the todo and set from and to time.</p>
  
  <p>I have added 4 fields in my render function. Please guide me if my approach is wrong. at the end I want have an array todolist with index element and subarray index element as date and and children elements have todo, from and to time.</p>
  
  <p>example: </p>
  
  <pre><code>todolist[
      27-06-2018 : [
         todo: eat breakfast
         from: 9:00
         to: 9:30
      ]
      28-06-2018 :[
         todo: eat lunch
         from: 12:00
         to: 12:30
      ]
  ]
  </code></pre>
  
  <p>for the above requirement how to initailaize the state?</p>