Aggregation practice

Mess around with aggregations. There's nothing special about them, there's nothing magic about them. Play around with the sample enron email data.

There are two aggregates to create as part of this repo: lib/emails-per-day.js and lib/email-recipients.js. Fill in the array with aggregation stages. Once correct, the tests in test/aggregate.test.js should pass.

There are some hints provided. Be careful of potential spoilers there. Try to use the hints only if you get stuck.

If you really get stuck, or just want to check your answer see the answers.

To check your answers run the provided tests.

Setup

A read-only db connection to an mlab database is provided by test/connect.js. Tests require an internet connection.

npm i
Run tests with npm run test or npm run test:watch

Example document

{
    "_id" : ObjectId("4f16fca5d1e2d3237100927d"),
    "body" : "Your just a little jokester today - What do you mean \"try and fit me in your schedule\"     I will be there - and you will make the time for me -Because you have NO OTHER CLIENTS!!!!\n\nthanks for the laughs\ni love you",
    "filename" : "23.",
    "headers" : {
        "Content-Transfer-Encoding" : "7bit",
        "Content-Type" : "text/plain; charset=us-ascii",
        "Date" : ISODate("2001-04-19T02:40:00.000Z"),
        "From" : "sandra.brawner@enron.com",
        "Message-ID" : "<11280155.1075845089118.JavaMail.evans@thyme>",
        "Mime-Version" : "1.0",
        "Subject" : "Re: Misc",
        "To" : [ 
            "kennethbrawner@email.msn.com"
        ],
        "X-FileName" : "Brawner, Sandra F..pst",
        "X-Folder" : "\\Brawner, Sandra F.\\Brawner, Sandra F.\\Sent Items",
        "X-From" : "Sandra F Brawner",
        "X-Origin" : "BRAWNER-S",
        "X-To" : "kennethbrawner  <kennethbrawner@email.msn.com>",
        "X-bcc" : "",
        "X-cc" : ""
    },
    "mailbox" : "brawner-s",
    "subFolder" : "sent_items"
}

Emails per day

Find the number of emails sent per day.

Email recipients

Find the number of emails sent to each email address. Sort the result in order of most received to least received.

MongoDB syntax

Stages

$unwind: make a new document for each item in an array Docs
project: select or manipulate fields in a document Docs
group: group by a field in a document Docs
sort: sort by a field. Docs

Operators

dateToString: format a date/time into a string. E.G. { $dateToString: { format: '%Y-%m-%d', date: '$headers.Date' } } Docs
sum: add numbers. Docs
addToSet: add item into an array, removing duplicates. Docs
size: get the size of an array. Docs
min: get the minimum value seen for a field in a group by. Docs
max: get the maximum value seen for a field in a group by. Docs
avg: get the average value seen for a field in a group by. Docs

AaronD87/enron-aggregate