Data Team Challenge

Problem

Not familiar with nested sets? Read this.

With the switch to event streams, we will switch to calculating the nested sets on the fly on our side as opposed to receiving them in full from the source every time a change is made.

Requirements

1. App must be implemented in NodeJS
2. Read full test.tree table into a program. Calculate the lft and rgt values for the nested sets. Result should match the lft and rgt values in the test.tree table.

Challenge needs to be completed outside of regular work hours. We suggest spending at least 2 hours on the challenge but no more than roughly 5 hours.

Competition

Consideration will be given to the following for scoring:

1. Program runs and completes the calculation of the nested sets (lft, rgt) values
2. Correctness of the nested sets
3. Average Speed of execution over multiple iterations
4. Use of proper idiomatic patterns in NodeJS
   • Promises
   • async/await
   • Dependency Injection
   • Testability
   • Linting (standard is nice)
5. Unit Tests
6. Enforced automated linting / tests when committing code

A strawman folder for an node project running within docker

• Folder src/ contains the node application.
• Folder docker/ contains the docker build bits, with support for multiple environments in each sub folder
• The launch script for dev is docker/{env}/app/launch
• The ./local command is a useful wrapper for docker-compose. It prints out what it is running, so you can adjust to suite your needs. You can get a full syntax by just running the command ./local

Developing

Run the app container:

./local dev up

Connecting a shell

You can connect a shell to your running service with:

./local dev sh

Running a command against the docker container

./local dev sh -c "echo hello"