javascript - ReactJs: How to update property of state -

i trying update isselected property row of data stored in state, property doesn't update can please tell me best way this?

        var selectedidspush = [];         var selectedidspush = this.state.contacts.slice();         for(var i=0;i<selectedidspush.length;i++)         {             var idasnumber = parseint(id);              if (page.state.contacts[i].id === idasnumber) {                 page.state.contacts[i].isselected = true;                 break;             }          } 

reacts wants consumers setstate instead of assigning properties directly. in example, build , assign new contacts list using:

var idasnumber = parseint(id); var newcontacts = this.state.contacts.map(function (contact) {   if (contact.id === idasnumber) {     contact.isselected = true;   }   return contact; });  this.setstate({ contacts: newcontacts });