MongoDB & Node.js Final 2 - Please use the Enron dataset you imported for the previous problem. For this question you will use the aggregation framework to figure out pairs of people that tend to communicate a lot. To do this, you will need to unwind the To list for each message. This problem is a little tricky because a recipient may appear mor…

final2.js

use enron
db.messages.aggregate([
  {
		$unwind: "$headers.To"
	},
	{
		$project: {
			"_id": 1,
			"headers.From": 1,
			"headers.To": 1
		}
	},
	{
		$group: {
			_id: { id: "$_id", from: "$headers.From", to: "$headers.To" },
			count: { $sum: 1 }
		}
	},
	{
		$group: {
			_id: { from: "$_id.from", to: "$_id.to" },
			count: { $sum: 1 }
		}
	},
	{
		$sort: {
			count: -1
		}
	},
	{
		$limit: 5
	}
])