coding-dojo

The purpose of this dojo is to practice TDD and pair programming.

Context of the dojo

We focus on generating prime numbers from an integer. Out of the box, the project is capable of generating primes for numbers up to 3 (yeah!). Your goal is to improve this.

Setting up

• Clone the repository
• npm install

Running

• npm start

The prime number generator is a REST api available from http://localhost:8080/prime/3 (to get primes of number 3).

Testing

The project comes with unit tests developped with mocha. Running the tests is done with npm test.

A watch mode is available (to run the tests automatically after modifying a file) through npm run test:watch.

Exercise 1

Extend the prime number generator to support numbers at least to 200.

BONUS (if you have time): Implement a limit in the web service to fail the call if the requested number is greater that the limit.

Exercise 2

Provided the list of prime numbers returned for X (named Px), if you request the primes of Y with X < Y, we know that the result will contain Px.

Implement a cache that accepts a number and its associated prime numbers. The interface would look like :

const cache = new Cache();
cache.get(1); // undefined
cache.set(4, [1, 2, 3]);
cache.get(4); // [1, 2, 3]
cache.get(3); // [1, 2, 3]
cache.get(2); // [1, 2]
cache.set(5, [1, 2, 3, 5]);
cache.get(5); // [1, 2, 3, 5]
cache.get(6); // undefined

And implement the following acceptance criteria:

• Cache read API
  • Provided the cache is initialized with 4 and [1, 2, 3] as its prime numbers
    • it returns the primes for 1 (i.e. [1])
    • it returns the primes for 2 (i.e. [1, 2])
    • it returns the primes for 3 (i.e. [1, 2, 3])
    • it returns the primes for 4 (i.e. [1, 2, 3])
    • it returns undefined if the cache does not know the list of primes for a given number
• Cache write API
  • Provided the cache is empty
    • it accepts a number and its prime numbers
  • Provided the cache is initialized with 4 and [1, 2, 3] as its prime numbers
    • it ignores known prime values
    • it accepts bigger values with their prime numbers
    • it increments the list of primes