Separate data from datahash

I am working on a Dimple/D3 chart that plots missing days' data as 0.

date                fruit   count
2013-12-08 12:12    apples  2
2013-12-08 12:12    oranges 5
2013-12-09 16:37    apples  1
                             <- oranges inserted on 12/09 as 0
2013-12-10 11:05    apples  6
2013-12-10 11:05    oranges 2
2013-12-10 20:21    oranges 1

I was able to get nrabinowitz's excellent answer to work, nearly.

My data's timestamp format is YYYY-MM-DD HH-MM, and the hashing + D3.extent time interval in days results in 0-points every day at midnight, even if there is data present from later in the same day.

An almost-solution I found was to use .setHours(0,0,0,0) to discard the hours/minutes, so that all data would appear to be from midnight:

...
var dateHash = data.reduce(function(agg, d) { 
 agg[d.date.setHours(0,0,0,0)] = true; 
 return agg; 
}, {});
...

This works as expected when there is just 1 entry per day everyday, BUT on days when there are multiple entries the values are added together. So in the data above on 12/10: apples: 6 , oranges: 3.

Ideally (in my mind) I would separate the plotting data from the datehash, and on the hash discard hours/minutes. This would compare the midnight-datehash with the D3 days interval, fill in 0s at midnight on days with missing data, and then plot the real points with hours/minutes intact.

I have tried data2 = data.slice() followed by setHours, but the graph still gets the midnight points:

...
// doesn't work, original data gets converted
var data2 = data.slice();
var dateHash = data2.reduce(function(agg, d) { 
 agg[d.date.setHours(0,0,0,0)] = true; 
 return agg; 
}, {});
...

Props to nrabinowitz, here is the adapted code:

// get the min/max dates
var extent = d3.extent(data, function(d) { return d.date; }),
  // hash the existing days for easy lookup
  dateHash = data.reduce(function(agg, d) {
      agg[d.date] = true;

// arrr this almost works except if multiple entries per day
//    agg[d.date.setHours(0,0,0,0)] = true; 

      return agg;
  }, {}),
  headers = ["date", "fruit", "count"];

// make even intervals
d3.time.days(extent[0], extent[1])
    // drop the existing ones
    .filter(function(date) {
        return !dateHash[date];
    })
    // fruit list grabbed from user input
    .forEach(function(date) {
fruitlist.forEach(function(fruits) {
        var emptyRow = { date: date };
        headers.forEach(function(header) {
            if(header === headers[0]) {
                emptyRow[header] = fruits;}
            else if(header === headers[1]) {
                emptyRow[header] = 0;};
    // and push them into the array
        data.push(emptyRow);
    });
// re-sort the data
data.sort(function(a, b) { return d3.ascending(a.date, b.date); });

(I'm not concerned with 0-points in the hour-scale, just the dailies. If the time.interval is changed from days to hours I suspect the hash and D3 will handle it fine.)

How can I separate the datehash from the data? Is that what I should be trying to do?