JSFiddle - React, Tailwind, and code Playground

JavaScript

// Part 1

var res_string = '[{"deviceId": "9092eab10f4","name": "temperature","timestamp": "2017-06-13T13:19:59.673Z","value": 21.5},{"deviceId": "9092eab10f4","name": "temperature","timestamp": "2017-06-13T13:19:59.673Z","value": 21.5}]'

console.log("Start - Part 1");

var new_res_from_string = {"data": JSON.parse(res_string)}
console.log(new_res_from_string);

console.log("End - Part 1");

// Part 2

console.log("Start - Part 2");
var res_arr = [
  {
    "deviceId": "9092eab10f4",
    "name": "temperature",
    "timestamp": "2017-06-13T13:19:59.673Z",
    "value": 21.5
  },
  {
    "deviceId": "9092eab10f4",
    "name": "temperature",
    "timestamp": "2017-06-13T13:19:59.673Z",
    "value": 21.5
  }
];

var new_res = { "data" : res_arr }

console.log(new_res);

console.log("End - Part 2");