using map build array from big array

var tasks = [
  {
    'id'       : '001',
    'name'     : 'Write for Envato Tuts+',
    'duration' : 120
  },
  {
    'id'       : '002',
    'name'     : 'Work out',
  },
  {
    'id'       : '003',
    'name'     : 'Procrastinate on Duolingo',
    'duration' : 240
  }
];

console.log("-- Daftar Task --");
console.log(tasks);

console.log("\n");

var task_names = tasks.map(function (task, index, array) {
    return task.name;
});

console.log("using map");
console.log(task_names);

console.log("\n");

var fildata = tasks.filter(function(task){
    return task.duration == 120;
});
console.log("using filter");
console.log(fildata);

console.log("\n");

// sort duration and sum it number
var total = tasks.map(function (task, index, array) {
    if(typeof task.duration !== 'undefined') {
        return task.duration;   
    }else{
        return 0;
    }
}).reduce(function (a,b) {
    return a+b;
});
console.log("using reduce");
console.log("Total duration: "+total);