Quantified Self A calorie tracker project for the fourth module


Pearson’s Law:

“That which is measured improves. That which is measured and reported improves exponentially.” - Karl Pearson

Technology has enabled us to measure more, and shorten the period between measurement and reporting. Sensors are cheaper and smaller, computers are everywhere, and we can access data from anywhere. People who have recognized this, and applied it to themselves are part of a movement called “Quantified Self.”

You are going to build a simple calorie tracker.

Learning Goals

  • Students apply knowledge of Ruby collections to JavaScript arrays
  • Students create and use functions with parameters
  • Students apply good coding conventions to JavaScript functions
  • Students organize functions into classes and objects
  • Students make effective use of this in multiple contexts
  • Students unit test JavaScript
  • Students use event listeners to attach code to event-element combinations including document-ready and element-click
  • Students write precise CSS-style selectors in multiple contexts like DOM manipulation and integration testing
  • Students read form content and manipulate DOM via JavaScript
  • Students integrate outside data sources in the browser (AJAX, local storage)
  • Students use integration testing to verify JavaScript functionality
  • Students implement a stand-alone web service with Node and Express
  • Students interact with SQL databases by writing raw SQL
  • Students use pull requests to organize discussion about features
  • Students implement feedback from a code review to improve quality
  • Students use an agile process to turn acceptance requirements into deployed software

Requirements Overview

Your requirements for the application are detailed in the cards you’re going to import to Pivotal Tracker (you can also find them here), but here’s an visual of what you’re doing:


You’ll be building two main layouts for this project. A “foods” index page and a “diary” index page (as seen below).

Manage Foods


Main Diary


Broad Front End features

  • CRUD foods
  • Add a food to a meal
  • Compare calories to goals (meal and total)
  • View calorie calculations in diary
  • The page must not refresh while users are interacting with it
  • Data persists across refreshes
  • EXTENSION: Build an admin panel to manage data
  • EXTENSION: Add offline functionality

Broad Back End features

First, we’ll have our Front End talking with a pre-built Rails API found here. During week 3 of this project, we’ll introduce Node, Express, and Knex and you’ll build a new backend using only JavaScript! In a sense, you’ll be replicating the exisiting Rails API in Node (super cool).

Getting your project started

  • You’ll have two separate code bases to complete this project. You’ll have a code base for your front end and a separate code base for your back end. You may run into some errors when trying to communicate between the two code bases (most likely CORS problems), but we’ll address this in class when we discuss AJAX.
  • We’ll be starting with the front end so you’ll want to follow the instructions on the Quantified Self Starter Kit to get your codebase going.
  • As mentioned previously, you’ll be starting with the backend Rails API here. Fork this repository, run the setup commands, push it to production (your own heroku app), and use this as your source of data.
  • When you start to re-build the backend with Node, you’ll start your new backend repository from scratch.
  • You’ll need to accept your email invitation from Pivotal Tracker and use this as your Project Management tool.
  • Import this CSV to your project to get all the cards in there. Import is found under settings. Note - these user stories are for the functionality dealing with the front end only. When you get to the backend, you’ll need to write your own stories.
  • Add your assigned Technical Lead to your Pivotal Tracker and your repository.


  • Use whatever you’ve used in the past for schema, documentation and user stories. Or something new you’ve been wanting to try out. These things are graded on completion. Probably want to agree on a format in your DTR.
  • Allowed libraries are jQuery, lodash/underscore, and moment.
  • Logic like sorting, filtering, and validation should be done without using another library (except those listed in the previous point). These are great opportunities to abstract logic for unit tests.
  • All elements from the mockup should be represented in your app, even if the styling or layout is different. Unless it is mentioned specifically in the user stories, colors and other styling are up to you. You’ll be just fine if it looks exactly like the mockup though.
  • Details, Details, Details!!! If it’s in the user stories, we’re looking for it in your app. Please ask before you add any additional functionality. The job is to build what is asked for, and get any improvements approved first.
  • This is a 2 week project without any scheduled instructor check ins. We expect that you’ll be tagging instructors in PRs on Github wherever you’d like feedback. We also expect that if you feel like your team is falling behind, that you’ll reach out for extra support.

Tips for success

  • Try to use HTML/CSS classes when changing styling, instead of changing the styling of an element directly.
  • Experiment with ES6, but try to be consistent in each file whether you’re using ES6 or ES5. Probably the most useful thing in ES6 is string interpolation and multi-line strings, neither of which are supported in ES5.
  • There is similar functionality across elements in the app. Make your code DRY, but don’t over do it. Sometimes the functionality differs slightly.
  • Plan, diagram and break down the problem, but don’t try to get it right the first time. Don’t write too much code without refactoring. Maybe stop and refactor every so many minutes, or so many cards.
  • A lot of this is new, and you’ll probably have to be pairing more often, or at least be available to each other remotely.
  • Materialize is just a headache, but we can’t stop you from using it. Use whatever tool you’d like for styling.
  • Research content-editable. It will save you a lot of time for the editing foods functionality.
  • There’s a lot in this document. Refer back frequently.
  • If there’s any question about functionality, ask. There’s a #qs-questions channel specifically for this.


  • Create a full-stack JS application across two codebases
  • Be able to organize your JS across different files
  • Make AJAX calls to connect your front-end with your back-end
  • Handle events
  • Handle events fired on DOM elements that didn’t exist at load
  • Manage state via jQuery
  • Handle multiple DOM and data changes on single event
  • Write unit and integration tests in Javascript
  • Start to understand how full-stack JS applications work in practice, without a whole lot of explicit explanation


You will be subjectively (Friday of Week Three via Github) graded by an instructor on the following criteria:

Specification Adherence

  • 4: Application implements all functionality as defined, with no bugs, and one extension (if you choose to put your point here)
  • 3: Application implements all functionality as defined, but some bugs or strange behavior where features intersect
  • 2: Application is missing required functionality, deviates significantly from the spec, or serious bugs prevent features from being usable
  • 1: Application is missing a significant portion of functionality

Planning and Design

  • 4: Team created visual schema, API documentation and user stories, before writing tests. API adheres to REST standard.
  • 3: Team created either a schema or API docs to facilitate implementation of a service.
  • 2: Team has some notes on how to implement their service, but someone else couldn’t implement it.
  • 1: Team did not design their service.


  • 4: All functionality is covered by tests. Appropriate mix of unit and integration tests. Sad path testing in both unit and integration tests.
  • 3: All back-end functionality is covered by tests. Front-end uses unit tests wherever logic can be separated from interface and network requests.
  • 2: More back-end functionality implemented than tested and/or very little front-end testing
  • 1: Team fails to effectively test the application.


  • 4: Team put some effort into styling. HTML features unique IDs, classes and data attributes for DOM traversal.
  • 3: Application is not confusing to use. HTML classes and IDs are kebab case.
  • 2: HTML is greatly lacking in standards compliance. UI is confusing or very buggy.
  • 1: Application is unusable

JS syntax and Style

  • 4: Javascript features explicit DOM traversal (not using closest), demonstrates great OOP concepts, and uses named and anonymous functions when appropriate
  • 3: Code logically divided into files. Developer can show examples of good coding practices, like DRY and separation of concerns. Attention payed to indentation and naming.
  • 2: Javascript is noticeably lacking in the above concepts.
  • 1: Team has not applied any style concepts from class or from Ruby background

Git Workflow

  • 4: Team uses master for production, and creates a feature branch for each card worked on. Team is using pull requests with good context and conversation
  • 3: Team is using the feature branches for small groups of cards, and has a pull request for each feature. Developers that aren’t on the team have commented on PRs.
  • 2: Team fails to use feature branches, or isn’t using pull requests
  • 1: All code is committed to master

Project Management

  • 4: Team is using a project management tool and updating their progress daily. Team is approving each other’s work. Team is documenting conversations and conclusions on relevant cards.
  • 3: Team is using a project management tool to keep their project organized.
  • 2: Team is using a project management tool but didn’t update the progress frequently. Many cards have no changes made to them
  • 1: Team failed to use a project management tool to track its progress.

Extensions: Risk Taking

Adhering to any of these additional specifications will allow you to increase one score above:

All functionality is part of a class, written using ES6

You’ll learn about classes and ES6 during the course of this project. If you can fit all of your JS into classes, using ES6 syntax, you’ll get one extra point to add to a rubric score.

No Libraries (except for testing).

A big part of this project is writing JS functionality that you could have borrowed from a library. We’ve listed a few allowed libraries above. jQuery is still used in most legacy codebases, and JS is sorely missing most time manipulation. Accepting this challenge will require you to write more code, but it will give you a better handle one what is built into JS.

The exception is testing. There’s not any reasonable way you’ll be able to test without mocha and selenium.

Multiple Sources of Truth

Local Storage is often used for “offline” functionality. When the user is having trouble connecting to the internet, the application will continue to function. When a connection is re-established, the local changes are uploaded to the server. Likewise, if changes are made on one client, they should be downloaded to another client

Use Local Storage and AJAX to meet the following requirements:

  1. If I’m disconnected from the internet, I can continue to use the application.
  2. When I make a change while disconnected from the internet, that change will be uploaded to the server when I reconnect
  3. If I make a change on one computer, those changes should propagate to any other clients through the server. You do not need realtime functionality. These changes can occur after a refresh.

You will probably need to use a concept called service workers


Instead of building a single service, build a series of microservices. Each microservice is a separate codebase and application that represents a single table in your schema. These applications communicate with each other via HTTP. Since they all live in the same datacenter, this is not much of a performance problem.

The architecture would look something like this:


If you attempt this challenge, your planning and design should include your microservices architecture.

As to why you might want to do this, watch Chad Fowler’s Rocky Mountain Ruby 2015 talk