JSFiddle - React, Tailwind, and code Playground

JavaScript

var items = { 
  "a": {
    "x": 1
  },
  "b": {
    "y": 2
  },
  "c": {
    "z" : 3
  }
};

var something = [];

for ( var key in items ) {
  var item = items[key];
  if ( items.hasOwnProperty(key) ) {
    for ( var i = 0; i < 2; i++ ) {
      item.number = i;
      something.push(item);
    }
  }
}

console.log(something);