Array by key, value

array-key-value

var users = [];

users['john'] = { id: 'john01', role: 'admin' };
users['bob'] = { id: 'bob01', role: 'reader' };

console.log(users);
console.log(users['bob']);
console.log(Object.keys(users).length)

/*
   -- DOC --
   var users = new Array();
   new Array requires a name lookup on Array (you can have a variable with that name in scope), whereas [] does not.
   The relatively small difference in performance supports this point I think. You could do the same test with the Object and object literal {} by the way.

   users.length, gives you the next index available in the array.
   
*/