JSFiddle - React, Tailwind, and code Playground

HTML

<label id="lbl"></label>

JavaScript

var data='[ [new Date("2015/08/04 16:33:05"), 26.2, 15.0, 36.0], [new Date("2015/08/04 16:38:05"), 26.0, 15.0, 36.0], [new Date("2015/08/04 16:43:05"), 26.2, 15.0, 36.0], [new Date("2015/08/04 16:48:05"), 26.1, 15.0, 36.0], [new Date("2015/08/04 16:53:05"), 26.2, 15.0, 36.0 ], [new Date("2015/08/04 16:58:05"), 26.2, 15.0, 36.0], [new Date("2015/08/04 17:03:05"), 26.3, 15.0, 36.0], [new Date("2015/08/04 17:08:05"), 26.3, 15.0, 36.0], ]';

var arr = eval(data);
document.getElementById('lbl').innerText='Array length :  '+arr.length;