Sort array by date substring

[GessWurker1]

In a web app for which I'm responsible, I've been asked to sort contents of a form field by date descending using the date that starts each list item. I'm supposed to do this either onBlur or perhaps onSave because users are entering stuff willy-nilly. In any event, though I can very easily sort items alphabetically using javascript's array sort() method, sorting by date substring descending is whole 'nuther kettle of fish. My head is spinning trying to find a way to do this. 'Tis beyond me.

Here's an example of what I'd need to sort by date descending:

•01/21/2013 - something happened; something else happened on 01/30/2013.
•04/02/2014 - John J. buys a new car
•02/25/2014 - We went to a movie. It was awesome, but a better one comes out on 12/31/2019.
•05/21/2012 - Let's keep sorting things.


Let's say the above is all included in a form field with id=myActivities. I'd like to, onBlur, get this:

•04/02/2014 - John J. buys a new car
•02/25/2014 - We went to a movie. It was awesome, but a better one comes out on 12/31/2019.
•01/21/2013 - something happened; something else happened on 01/30/2013.
•05/21/2012 - Let's keep sorting things.

Any brilliant sorters out there? I'm at your mercy.

By the way, in a windows app I can use to edit/update existing content, I use the (slightly proprietary looking) jscript code below. It works great, but it's simple alphabetical sorting. Nothing to do with substring dates.

****************************************

var sortBox = new Array("Events");

function onRecordSave()
{
var i;
var es = Application.entrySeparator;
var fieldBox; // box object
var fieldString; // contents of the box
var entryArray; // array of field entries

// This loop will sort the entries in each box listed
// above, individually.
for (i = 0; i < sortBox.length; i++)
{
fieldBox = Form.boxes(sortBox);
if (fieldBox) // ensure that the box exists
{
fieldString = fieldBox.content;
entryArray = fieldString.split(es);

// sort the entries using the JScript sort method
entryArray = entryArray.sort();
fieldString = entryArray.join(es);
fieldBox.content = fieldString;
}
}

}

 

[feherke]

Hi

The [tt]Array.sort()[/tt] method accepts a callback function as parameter to use it as comparator.

So in your above code you only need to change that call :

entryArray [teal]=[/teal] entryArray[teal].[/teal][COLOR=orange]sort[/color][teal]([/teal][highlight]compareDate[/highlight][teal]);[/teal]

Then implement the referred callback function :

[b]function[/b] [COLOR=orange]compareDate[/color][teal]([/teal]a[teal],[/teal] b[teal])[/teal]
[teal]{[/teal]
  [b]var[/b] aDate [teal]=[/teal] [gray]/* code to extract the date part from parameter a */[/gray]
  [b]var[/b] bDate [teal]=[/teal] [gray]/* code to extract the date part from parameter b */[/gray]

  [b]if[/b] [teal]([/teal]aDate [teal]==[/teal] bDate[teal])[/teal]
    [b]return[/b] [purple]0[/purple]
  [b]else if[/b] [teal]([/teal]aDate [teal]<[/teal] bDate[teal])[/teal]
    [b]return[/b] [teal]-[/teal][purple]1[/purple]
  [b]else[/b]
    [b]return[/b] [purple]1[/purple]
[teal]}[/teal]

Feherke.
feherke.github.io

 

[GessWurker1]

Thanks for the help. I think I'm getting closer, but I'm not quite sure how to share info between onRecordSave and compareDate. Here's what isn't working (I imagine because fieldString is empty?):


function compareDate(a, b)
{
var aDate = fieldString.match(rgx)[0];
var bDate = fieldString.match(rgx)[0];

if (aDate == bDate)
return 0
else if (aDate < bDate)
return -1
else
return 1
}

var sortBox = new Array("Events");

function onRecordSave()
{
var i;
var es = Application.entrySeparator;
var fieldBox; // box object
var fieldString; // contents of the box
var entryArray; // array of field entries
var rgx = /\d\d\/\d\d\/\d\d/;

// This loop will sort the entries in each box listed
// above, individually.
for (i = 0; i < sortBox.length; i++)
{
fieldBox = Form.boxes(sortBox);
if (fieldBox) // ensure that the box exists
{
fieldString = fieldBox.content;
entryArray = fieldString.split(es);

// sort the entries using the JScript sort method
entryArray = entryArray.sort(compareDate);
fieldString = entryArray.join(es);
fieldBox.content = fieldString;
}
}
}

 

[GessWurker1]

I'm thinking I need to fully-embed the compare function in onRecordSave() so all the variables are available?

 

[feherke]

Hi

You have to extract the date parts from the received parameters :

[b]function[/b] [COLOR=orange]compareDate[/color][teal]([/teal]a[teal],[/teal] b[teal])[/teal]
[teal]{[/teal]
  [b]var[/b] aDate [teal]=[/teal] a[teal].[/teal][COLOR=orange]match[/color][teal]([/teal][fuchsia]/\d{2}\/\d{2}\/(\d{4})/[/fuchsia][teal]).[/teal][COLOR=orange]reverse[/color][teal]().[/teal][COLOR=orange]join[/color][teal]()[/teal]
  [b]var[/b] bDate [teal]=[/teal] b[teal].[/teal][COLOR=orange]match[/color][teal]([/teal][fuchsia]/\d{2}\/\d{2}\/(\d{4})/[/fuchsia][teal]).[/teal][COLOR=orange]reverse[/color][teal]().[/teal][COLOR=orange]join[/color][teal]()[/teal]

  [b]if[/b] [teal]([/teal]aDate [teal]==[/teal] bDate[teal])[/teal]
    [b]return[/b] [purple]0[/purple]
  [b]else if[/b] [teal]([/teal]aDate [teal]<[/teal] bDate[teal])[/teal]
    [b]return[/b] [teal]-[/teal][purple]1[/purple]
  [b]else[/b]
    [b]return[/b] [purple]1[/purple]
[teal]}[/teal]

Note that your regular expression only took the century of the year.
And extracting the entire date in a single piece does not make it better sortable. You have to move the year in front of month and day, so captured it and reversed the groups.


Feherke.
feherke.github.io

 

[GessWurker1]

Thanks! All good, now!

 

[Offera]

You tried github already?