Question

As I’ve gotten to know JS better, I’ve moved from a procedural style to semi-OO (don’t ask me what I mean by that: a mess basically!) but now I want to start using it properly. OO appeals to my coding-brain.

However, I’m trying to develop a library of school weeks, and I’m not sure how I’d best go about it.

If I was to simply use an array of weeks, they would look something like this:

    WeeksArray[36].StartDate = "2011-09-05";
    WeeksArray[36].EndDateSchool = "2011-09-09";
    WeeksArray[36].EndDateProper = "2011-09-11";
    WeeksArray[36].JSDate = new Date ( 2011, 8, 05 );
    WeeksArray[36].Type = "1";
    WeeksArray[36].Label = "Week 36: 5th Sept 2011";

• Key: Week number according to School Calendar
• StartDate / EndDate: MySQL-compatible date ranges
• JSDate: JS date object of start of week
• Type: school timetable, week 1 or 2
• Label: human-readable label indicating start of week

I would like this library to be accessible by other scripts, so that they can load an Array or Object containing all of the weeks in the school calendar. I’d imagine, for instance, one of my scripts producing a drop-down menu from this information, which displays “Week 36: 5th Sept 2011” and when clicked upon sends a request to my PHP script & SQL database then filters the information on screen accordingly. NOTE: I don’t need help with the implementation of the latter, it’s just an example for context.

I started coding as follows:

var LEAP = {}

LEAP.Schedule = {

    init: function() {
        this.setWeeks();
    }

    setWeeks: function() {
        var WeeksArray = [];

But the more I look at it, the less correct it feels!

Should I be creating “Week” objects, then a container for them which has a method to return all of the Week objects? I’ve been reading the OOP chapter in “Pro JavaScript Techniques” by John Resig, but truth be told I don’t fully understand it. This feels like the right approach, but an Object within an Object is hurting my head.

The final outcome should be that I include this script on one of my pages, then can use something like var WeeksArray = LEAP.Schedule.getWeeks();, but even then I’m not sure that’s realistic?

I’m rather confused…! 😀 Any help on the subject would be hugely appreciated.

Answer 1

setWeeks: function(){
  var WeeksArray = []; //This variable is private, which is probably not your desired result.
}

^ That doesn’t work, see comment.

I’d recommend something like this:
External file:

var LEAP = {};
LEAP.Schedule = function(){//init
  //all events which should only occur once should be called here
  //Create the initial objects, e.g.
  this.weeks = [];
  this.calculateWeeks();
}
LEAP.Schedule.protoype.calculateWeeks = function(){
  for (var i=0; i<52; i++){
    this.weeks.push(Math.random()); //For the sake of the example ;)
  }
}
LEAP.Schedule.prototype.getWeeks = function(){
  return this.weeks;
}

Main file:

var Scheduleobject = new LEAP.Schedule();
var weeks = Scheduleobject.getWeeks();

This feels like a very natural OOP approach, to me.
You can even change the LEAP.Schedule function such that it returns the Weeks array immediately, dependent on the situation.

EDIT

An example of a week class:

LEAP.Schedule.week = function(n_year, n_month, n_day, n_week){
  //add code to validate the input
  //...
  //finished validating, processing:
  this.year = n_year;
  this.month = n_month;
  this.day = n_day;
  this.week = n_week;
}
LEAP.Schedule.week.protoype.getStartDate = function(){
  return year + "-" + pad(month) + "-" + pad(day);
}
//LEAP.Schedule.week.prototype.*Date are defined in a similar way
//The "EndDateSchool" and "EndDateProper" variables always follow the same pattern. Reduce the number of unnecessary variables by calculating these variables in the prototype function.
LEAP.Schedule.week.prototype.getLabel = function(){
  return "week" + this.week + ": " + this.day + (day==1||day==21||day==31?"st":day==2||day==22?"nd":day==3||day==23?"rd":"th") + " " + ["jan", "feb", "mar", "etc"][this.month-1] + " " + this.year;
}
function pad(n){return n>9?n:"0"+n}//a simple function to add a zero for your specific cases.

The week class can be called in this way:

var week = new Schedule.Week(2011, 8, 5, 36); //or this.Week(2011, 8, 5, 36) from the contex of the class.
var startDate = week.getStartDate(); //example`