Childrens Game (nodejs)

Pre-requisites: Nodejs v7.2.0
Install dependencies: npm install
Run game: npm run game -- --noOfChildren 5 --hopCount 3
Run tests / coverage: npm run cover

Out of scope

• Input validation

Assumptions

• Game always starts from the first child

Terminology

• noOfChildren (n)
• hopCount (k)

Design

• Focuses on simple, clean, testable code.
• Core game logic in /lib (independent of execution context).
• Children are represented as items in an array. Elimination logic uses a simple modulo operation to circulate the array and eliminate each child after the given hop count.
• Elimination logic isolated to separate class following SRP (could potentially evolve to strategy pattern if additional elimination techniques must be supported).
• All /lib classes define immutable methods so there are no side effects.

Alternate design?

• Make /lib/game.js asynchronous to prevent blocking calls and potentially allow consumers to subscribe to specific events for more fined grained control. e.g. UI / Console could subscribe to an eliminated event and re-render itself as each child is eliminated rather than just once at the end.