raininglemons/red-badger-test

Coding Challenge 2017

Blurb

I think this test probably took me around 2 hours. Getting through the main logic took me perhaps 45 minutes, and I spent the result cleaning bits up (i.e. allowing for logging when in 'debug' mode, adding comments, tests etc.).

I've deliberately assumed that the input will always be of the correct syntax. So it will fail without useful errors when the input file is incorrect.

Also as I didn't want to go beyond the time specified in the test, there are a few places for improvement given more time;

• The Grid class could store the "scents" much more efficiently. Whilst on a small scale is absolutely fine to iterate through past Robot instances and see where they've fallen off the grid. If we happened to scale it up, it would probably be more efficient to register "scents" in an array that only contains enough spaces for the grid rim.
• More useful errors with respect to an input of an invalid format
• More tests. Most have focused around basic functions within the Robot and within the grid using mostly sample data provided in challenge.
• Node version test, or at least some kind of transpiled alternative. Current test assumes the latest version of Node.
• Better handling of errors in the main script instead of always failing on a success code.
• Oooh also, since moving my code at work to react, I've done all new code with flow.js typing. I'd have liked to have added this, as particularly it's great with Intellij/Webstorm and it's great for preventing bugs in the build process. Deliberately left it out as this is a pure node application so wanted to avoid any kind of transpiling as it wasn't necessary on this small an app.
• Test mentions that there should be scope to add more commands. Currently there is a switch statement which should be simple enough to add new commands to. Thought about adding a dictionary of commands to the functions for executing them but thought in this size of a script going that far would be a bit of over-engineering.
• The maximum value for any coordinate is 50. Wasn't sure whether this was a restriction and the world should be capped at 50 x 50. Or this was more to help in developing to suggest that we wouldn't need to account for a grid greater than this size. Allowed for an infinite size of grid. In practice would have gone to requestor to clarify. Changed to disallow grid's greater than 50. With hindsight, this is what was required.

How to run

You know the drill...

    yarn install

or -

    npm install

Run tests

To run basic Jest tests use the following command:

    yarn test

or -

    npm test

Run on an input file

Run with sample file input:

    yarn start source.txt

or -

    npm start source.txt