Javascript Peculiarity

I was trying to write a syntax parser, and everything was going just great until I came across this little tidbit. In parsing this syntax:

obj.prop1.prop2.substring(0,1) I'd parse and evaluate obj, then find properties in it like so: var currentContext = null; code.split("."); for each (token in split string){ if (currentContext == null) currentContext = evaluate(token); else if (token in currentContext) currentContext = currentContext[token]; }

Evaluate executes code and returns objects within a context global to the method call, not the local context, which I call here, "currentContext"

But then I got an error trying to do stringProperty.substring(0,1). Can't call "IN" on a string? So I'm like, ok, let me try something else

if (token in Object.getPrototypeOf(currentContext)

And guess what... That shit don't work! Cannot call getPrototypeOf on a non-object. But it's a string?!

So I just ended up doing, if (token in String.prototype), just to say F YOU JAVASCRIPT!!! Otherwise I love Javascript. If you have any insight on this, PLEASE feel free to leave a comment.

I wrote up a JSFiddle for it, please link your own in the comments

This site now running on MongoDB 2.4.3

It does not take advantage of it in any way though... But I wanted to get it updated because a new site I'm writing takes advantage of some new features, like aggregate. Fun stuff!

MongoDB has an aggregate method

And I'm writing a disc golf score keeping and statistics tracking application.  I wanted to see what course a particular user played the most.

db.scores.aggregate([{$match: { user: userId } }, {$group: { _id: { course: "$course", variant: "$variant", tees: "$tees" }, played: { "$sum": 1 } } }]);

It shows that in the score keeping data, I've played the Blue Tees at the Front Nine at Sedgley Woods 6 times, and the Back Nine 5 times, since last year.


I will be able to use this to get a whole bunch of different statistics :)  I will make an announcement when that goes live, I want to put it on the web, it'll be fun.  It's written on my latest of the software I'm writing in Node.js.

This one is a C# post

At work, I was working on cool stuff, but then my boss was like "I need this report and this report and this report. Thanks."

I'm not one to turn down such a politely worded and completely fictitious request. Reports are easy until the requests become stuff like "Include subtotal line for every Apple category and Orange category"

My data set was obviously not Apples and Oranges, but here's what I did to quickly and easily make subtotals for each of these

First, I made some C# Attributes, which are nice when you like to work in the meta.

public class MyReportItem { [SubtotalGroup(GroupName = "Fruit Type")] public string FruitType { get; set; } public string FruitName { get; set; } [SubtotalSum] public int Count { get; set; } [SubtotalAverage] public int SalesPerDay { get; set; } [SubtotalSummaryDesignator] public bool IsSubtotalLine { get; set; } [TotalDesignator] public bool IsTotalLine { get; set; } }

Your SQL might look like this:

select FruitType, FruitName, StockQty, SalesPerDay from Fruits order by FruitType, FruitName

So your data looks like this

'Apple', 'Mcintosh', 12, 80 'Apple', 'Delicious Red', 22, 50 'Orange', 'Some Orange Name', 33, 90

The code I wrote allows that data to be quickly, easily, and automatically shown like this:

'Apple', 'Mcintosh', 12, 80 'Apple', 'Delicious Red', 22, 50 'Apple Subtotal', '', 34, 65 'Orange', 'Some Orange Name', 33, 90 'Orange Subtotal', '', 33, 90

Notice the "SalesPerDay" column has an average attribute on it, not a sum. Here's the meat of my code, after getting the attributes and the data all figured out.

public List<T> PopulateSubtotalItems() { List<T> withSubs = new List<T>(); if (this.list.Count == 0) return withSubs; // allow multiple group by with subtotals. e.g. group by Fruit Name and say fruit type, like "Citrus" // to subtotal Oranges and subtotal Limes and then subtotal Citrus List<GroupSub<T>> subs = new List<GroupSub<T>>(); foreach (string key in this.groupBy.Keys) { T sub = new T(); GroupSub<T> groupSub = this.groupBy[key]; groupSub.SubRecord = sub; // sets the properties which designate the group. So this subgroup might set FruitType to "Apple" this.SetGroup(groupSub, this.list[0]); // sets the bool property which the subtotal designator is on to true. this.SetSummary(groupSub); subs.Add(groupSub); } // if there's a bool property with the "TotalDesignator" attribute, include total GroupSub<T> totals = null; if (this.includeTotal) { T sub = new T(); totals = new GroupSub<T>(); totals.SubRecord = sub; totals.IsTotal = true; this.SetTotal(totals); // sets the property which the TotalDesignator is on to true } subs = subs.OrderBy(grp => grp.Sequence).ToList(); int grpCount = 0; for (int i = 0; i < this.list.Count; i++) { bool added = false, last = i == this.list.Count - 1; foreach (GroupSub<T> grp in subs) { bool same = SameGroup(grp, this.list[i]); if (!same) { this.Average(grp, grpCount); // set the average properties to the sum / grpCount withSubs.Add(grp.SubRecord); // add the subtotal record to the group grpCount = 0; // start afresh grp.SubRecord = new T(); this.SetSummary(grp); SetGroup(grp, this.list[i]); } Increment(grp, this.list[i]); if (last) // special handling on the last one. { this.Average(grp, grpCount); if (!added) { Increment(totals, this.list[i]); withSubs.Add(this.list[i]); added = true; } withSubs.Add(grp.SubRecord); grpCount++; } } if (!added) { Increment(totals, this.list[i]); withSubs.Add(this.list[i]); added = true; grpCount++; } } // add the total line if (this.includeTotal) { this.Average(totals, this.list.Count); // average the total record withSubs.Add(totals.SubRecord); } return withSubs; // that's it!! }

As you can see, I no longer have to dread doing subtotals on reports!