// I am creating an accounting app; the transactions are stored using the following doc:

{
   "_id": "405b791b64424d12e03c12e6e5001535",
   "_rev": "1-97d53ba31a6ebb8c0508d0fc8776fac5",
   "type": "transaction",
   "account": "account_id",
   "payee": "Gas Company",
   "description": "May Bill",
   "date": "2009/05/25",
   "status": "cleared",
   "category": "Bills / Gas",
   "value": -5000
}

// Or they can be split acroll multiple accounts / categories / etc. In this case split over two categories:

{
   "_id": "405b791b64424d12e03c12e6e5002532",
   "_rev": "1-da46384d5f9fbfd26acbf8fc9a8e82fe",
   "type": "transaction",
   "account": "account_id",
   "payee": "Credit Card Company",
   "description": "May Statement",
   "date": "2009/06/02",
   "status": "uncleared",
   "category": "Debt / Credit Card Payments",
   "value": -5000,
   "split": [
       {
           "category": "Dept / Default Charges",
           "value": -1000
       }
   ]
}

// I have made a view to display all the unique categories in use across all transactions.

// MAP
function (doc) {
    if (doc.type && doc.type == 'transaction') {
        if (doc.category) emit(doc.category);
        if (doc.split) doc.split.map(function (spl) {
            if (spl.category) emit(spl.category);
        });
    }
}

// REDUCE
function(keys, values, rereduce) {
    return true;
}

// CURRENT OUTPUT OF VIEW (with group=true)
{
	"rows": [
		{
			"key": "Debt / Credit Card Payments", 
			"value": true
		}, 
		{
			"key": "Bills / Gas", 
			"value": true
		}
	]
}

// CURRENT OUTPUT OF VIEW WHEN RUN AS A TEMPORARY VIEW (with group=true)
{
	"rows": [
		{
			"key": "Dept / Default Charges", 
			"value": true
		}, 
		{
			"key": "Debt / Credit Card Payments", 
			"value": true
		}, 
		{
			"key": "Bills / Gas", 
			"value": true
		}
	]
}

// SIMPLE TEST VIEW
function (doc) {
    if (doc.split) emit(null, doc.split);
}

// OUTPUT OF TEMP VIEW
{
	"total_rows": 1, 
	"offset": 0, 
	"rows": [
		{
			"id": "405b791b64424d12e03c12e6e5002532", 
			"key": null, 
			"value": [
				{
					"category": "Dept / Default Charges", 
					"value": -1000
				}
			]
		}
	]
}

// OUTPUT OF SAME VIEW AFTER SAVE
{
	"total_rows": 1, 
	"offset": 0, 
	"rows": [
		{
			"id": "405b791b64424d12e03c12e6e5002532", 
			"key": null, 
			"value": [
			]
		}
	]
}

/*
It seems from the above that couch is for some reason returning the splits field as an empty array.

Thanks for your time on IRC already.

Cheers

John
*/