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Treasure Hunter

A Learning TypeScript > Generics 🍲 entree project.

Good evening, professor. We're with the National Typeological Survey. We've received word that there is a new system of catacombs and tunnels beneath your city. We'd like you to explore them.

Please submit a collectTreasure function to us that can recursively sift through buried contents. We will provide you functions to determine what is fake, real, or general scrap.

Setup​

If you haven't yet, set up the github.com/LearningTypeScript/projects repository locally.

shell
git clone https://github.com/LearningTypeScript/projects learning-typescript-projects
cd learning-typescript-projects
npm i
shell
git clone https://github.com/LearningTypeScript/projects learning-typescript-projects
cd learning-typescript-projects
npm i

Change your terminal directory to this project's:

shell
cd projects/generics/treasure-hunter
shell
cd projects/generics/treasure-hunter

In one terminal, run the TypeScript compiler via the tsc script. For example, to start the TypeScript compiler in watch mode:

shell
npm run tsc -- --watch
shell
npm run tsc -- --watch

In another terminal, run Jest via the test script. For example, to start tests in watch mode:

shell
npm run test -- --watch
shell
npm run test -- --watch

Specification​

Export a collectTreasure function. It should have three type parameters: Content, Fake, and Real. Fake and Real should both extend Content.

The collectTreasure function should have three runtime parameters:

  • buried: A Buried object (see later) of Content data
  • isFake: A type predicate function that takes in a datum and returns whether it is Fake
  • isReal: A type predicate function that takes in a datum and returns whether it is Real

Also create and export a Buried interface with a single type parameter. Each Buried object can be one of three things:

  • An array of the same type of Buried objects
  • A NextArea object, which can be either:
    • A Catacomb shape, with properties:
      • contents: A Buried object of the same type
      • type: "catacomb"
    • A TunnelSystem shape, with properties:
      • tunnels: An array of Buried objects of the same type
      • type: "tunnels"

The collectTreasure function should return an object with three properties:

  • fake: Array of found Fake items
  • real: Array of found Real items
  • scrap: Array of all other items

Notes​

  • Don't use any or leave any implicit anys.