data = ["[Date.UTC(2016,09,30),250500.00]","[Date.UTC(2016,09,29),255100.83]", "[Date.UTC(2016,09,28),255600.82]"]

​

var parseItem = function(it) {

    var utcDateReplaced = it.replace(/Date\.UTC\((.*)\)/, function() {

      argsRaw = arguments[1];

      args = argsRaw.split(',');

      return Date.UTC.apply(Date, args);

    })

    return JSON.parse(utcDateReplaced);

}

​

var result = data.map(parseItem);

console.log(result); 

// ===> [[1477785600000, 250500], [1477699200000, 255100.83], [1477612800000, 255600.82]]

​