Flatten nested array created with d3.nest() to create stacked bar - d3.js

Question

I have data returned from a REST API in the following form.
[{
"created": "2014-06-01T11:21:47Z",
"is_good": false,
"amount": 10
},{
"created": "2014-06-01T12:01:00Z",
"is_good": false,
"amount": 12
},{
"created": "2014-06-02T10:00:00Z",
"is_good": true,
"amount": 8
},{
"created": "2014-06-02T08:00:00Z",
"is_good": false,
"amount": 3
},
...
]
In order to make a stacked bar chart, I thought the solution would be to use d3.nest() to rollup the amounts, first by date, then by is_good (the stacking category).
nestedData = d3.nest()
.key(function(d) { return d3.time.day(new Date(d.created)); })
.key(function(d) { return d.is_good; })
.rollup(function(leaves) { return {amount: d3.sum(leaves, function(d) { return d.amount; })}; })
.entries(jsonData);
That would probably be fine when drawing the chart following Mike Bostock's example here, but wouldn't work in a d3.layout.stack() call, because it requires the .values() to be the group iterable from which x and y is then calculated. That lead me to try the keys the other way around, but then drawing the chart itself becomes tricky.
So after all of that, I'm now wondering if there's a neat d3 way of flattening the nested values into something that resembles the datasets in almost all stacked bar chart examples.
Alternatively, perhaps I'm just not seeing how best to use the double nested data to create a stacked bar chart based on the examples.
Any help would be much appreciated.

Answer 1

I eventually decided to tackle this without using d3.layout.stack at all, and attempted to convert the double nested array into something resembling the example given. This is the code that will take that complex array and squash it down into something more manageable when drawing the chart.
data.forEach(function(d) {
var y0 = 0;
d.amounts = color.domain().map(function(is_good) {
return {is_good: is_good, y0: y0, y1: y0 += +d.values.filter(function(d) {
return d.key == is_good;
})[0].values.amount};
});
d.total = d.amounts[d.amounts.length - 1].y1;
});
Here's a working example.
I'm sure this isn't perfect, so if anyone has a better way of achieving the same result, I'd be interested to see it!