d3.nest example

nester.js

// Insert this at the top of the process() function
    
    // This part just converts the flat objec to a flat array, nothing fancy
    var flatty = [];
		_.each(data, function(obj, key) {
			if ( key !== 'keys' ) { flatty.push(obj); }
		});
		console.log(flatty);
		
		var nested_data = d3.nest() // create the nest object
		    // this is the top level groupby
		    // I'm just using the momen() function to conver the StartTime into the day of the month
				.key(function(entry){ return moment(entry.StartTime).date() }) 
				// this is the subgroup below the day of the month
				.key(function(entry){ return entry.Sponsor })
				// This is the third level where it's grouped by Task
				.key(function(entry){ return entry.Task })
				// I have no idea why the data is inserted last
				.entries(flatty);

		console.log(nested_data);