Codewars Challenges

My solutions to the Codewars challenges implemented in a few languages that interest me. I always do full TDD in everything I code, and these are no exceptions. Therefore, unit tests are provided as well.

Chicken Scheme

Install Necessary Eggs

For Scheme I use Chicken. Install these eggs:

$ chicken-install \
    test \
    srfi-1 \

Running Tests

To run the tests, make sure you are inside the directory that contains the file with the tests, for example:

$ ls -1
add.spec.scm
add.scm

Then, run this command

$ csi -quiet -batch

-- testing add ----------------------------------------------------
should add zeroes ......................................... [ PASS]
should add positive numbers ............................... [ PASS]
should add negative numbers ............................... [ PASS]
3 tests completed in 0.0 seconds.
3 out of 3 (100%) tests passed.
-- done testing add -----------------------------------------------

If running from Emacs + Geiser, make sure you execute run-geiser after you visit the .scm file you want to run, so that Geiser is in the directory of that file and the (load "...") directive does not fail saying it cannot find the files to load.

To run the tests from Emacs/Geiser, visit the spec file, start Geiser with M-x geiser and then do a C-c C-b (geiser-eval-buffer).

TypeScript

I use Deno to test and run the TypeScript solutions. Also be sure to check these notes about Deno and absolute imports plus editor setup on this very site.

Running Tests With Deno

Change to the root directory of where these codewars solutions have been cloned, e.g:

$ cd /path/to/devhowto/src/codewars

The run all tests, or specific tests:

$ deno test --unstable 6kyu
$ deno test --unstable 6kyu/friend-foe
$ deno test --unstable 6kyu/friend-foe/friend-foe.spec

Check extra options with deno test  --help | less.

Unstable APIs

We are making use of "deno.unstable": true in the project configuration and the use of the --unstable command line flag for running the tests because we are sometimes using unstable APIs, like Nested Testing API from Deno v1.15.

Here’s my setup:

$ sed '' .vim/coc-settings.json
 {
   "deno.enable": true,
   "deno.lint": true,
   "deno.unstable": true,
   "deno.importMap": "./import-map.json",
   "tsserver.enable": false
 }

Codewars Challenges Solved

• 6kyu
  • Find Int That Appears Odd Number of Times
    • Approach 1 (search and count)
    • Approach 2 Bitwise XOR
    • TypeScript
      • Unit Tests
      • Solution 1 (single function, approach 1)
      • Solution 2 (helper functions, approach 1)
      • Solution 3 (bitwise XOR)
    • Scheme
      • The Test Suit
      • v1 single function
      • v2 smaller, composable functions
        • Unit Tests for the Helper Functions
        • Implementation using the composed functions
      • v3 car cdr
        • Unit Tests for the Helper Functions
        • Implementation using car, cdr and null?
  • Which Are In
    • Approach 1
    • JavaScript
      • The Test Suite
      • Solution 1
    • TypeScript
      • The Test Suite
      • Solution 1
    • Scheme
      • The Test Suite
      • Solution 1
  • Friend or Foe
    • Approach 1
    • JavaScript
      • Unit Tests
      • Solution 1
    • TypeScript
      • Unit Tests
      • Solution 1
    • Scheme
      • Unit Tests
• 7kyu
  • Sort Numbers
    • TypeScript
    • v1 Sort Function Callback
  • Valid Parentheses
    • Intro
    • Haskell
      • v1
      • v2
      • v3
    • JavaScript
      • v1
      • v2
  • Vowel Count
    • Example Input
    • Haskell
      • v1
      • v2
      • v3
    • JavaScript
      • v1
      • v2
      • v3
  • Simple Fun: Diplomas
    • JavaScript
      • Solution 1
      • Solution 2