JSFiddle - React, Tailwind, and code Playground

JavaScript

var times = [1366004070000,1,1366004406000,1];
var local_times = [];
for(var i=0;i<times.length;i++){
     var time = times[i];
    if(time != 1){
        var d = new Date(time);
        var tz = d.getTimezoneOffset();        
        var tz_ms = tz*60*1000;
        time = d.getTime() - tz_ms;
    }
    
    local_times.push(time);
}

console.log(local_times);