Add Concept Exercise for 'randomness': Captain's Log

[quintuple-mallard]

This PR adds hints.md,introduction.md, instructions.md, config.json, design.md, exemplar.js, captains-log.js, and captains-log.spec.js to a new exercise on the JavaScript track.

A couple of questions to a reviewer:

• The other exercises have these files:
  .gitignore, .npmrc, LICENSE, package.json, jest.config.js, global.d.ts, eslint.config.mjs, and babel.config.js. These are not mentioned in the docs though. Should I add these, or does that happen automatically somehow?
• How do I generate a UUID?

[github-actions]

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[Cool-Katt]

If you've used configlet, which is our tool for managing tracks and things like generating exercices, then all the needed files should be auto-generated and you shouldn't need to manually attach a UUID, but in case you do configlet can also do that.

Also worth checking out our (slightly outdated) CONTRIBUTING guide.

[quintuple-mallard]

Errors in tests fixed, and for loops now used.

Just a question - is there a toInclude method?

[SleeplessByte]

(I wrote an entire thesis on how to calculate the expected number of rolls to get all the values in the planet class thing, but when I tried to submit it I pressed back accidentally and then lost it all. Will write it again soon...)

[SleeplessByte]

Just a question - is there a toInclude method?

Yes: toContain(item)

[SleeplessByte]

Okay. So I did this again.

In order to find out how many rolls we need to see each planet class in the following string:

'DHJKLMNRTY'

...we need to make a die that's fair with each side one class. There are 10 letters in the string. This math answer for a 6-sided die pointed me to terms to find this stats answer. We are looking for the 10 * harmonic(10) which is just shy of 30.

However, that gets us the average and we need to find out a reasonable number to use as maximum or at least a high probability (>95%, preferably >99.5%).

So I made this simulation in R.

Then I ran it 5 times:

29.2
   
Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
10.0    21.0    27.0    29.2    35.0   118.0 

29.2544

Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
10.00   21.00   27.00   29.25   35.00  131.00 

29.528

Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
10.00   21.00   27.00   29.53   35.00  118.00 

29.0984
Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
11.0    21.0    27.0    29.1    34.0   100.0 

29.53
Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
10.00   21.00   27.00   29.53   35.00   93.00 

This tells me that the average number is spot on, and that we can use 200 rolls to get all the values, but to make it completely improbable that a correct solution yields an incomplete set, we can do it 1_000 times.

describe('randomPlanetClass', () => {
  test('planet classes are valid',  () => {
    const expected = 'DHJKLMNRTY'
    const seen = {}

    for (let i=0; i < 1_000; i++){
      const actual = randomPlanetClass()
      expect(expected).toContain(actual)
    }
  })

  test('all planet classes can be returned',  () => {
    const expected = 'DHJKLMNRTY'
    const seen = {}

    for (let i=0; i < 1_000; i++){
      const actual = randomPlanetClass()
      seen[actual] = true
    }

    expected(Object.keys(seen).length).toBe(expected.length);
  })
    
  // remove the other test, it's no longer necessary
})

[quintuple-mallard]

Tests updated and uuid added.

[quintuple-mallard]

@SleeplessByte when I try to use corepack enable or pnpm install from the track's root directory I am given the message 'corepack' is not recognized as an internal or external command,
operable program or batch file. (or 'pnpm' is not recognized as an internal or external command,
operable program or batch file. , in the case of pnpm)

[SleeplessByte]

@SleeplessByte when I try to use corepack enable or pnpm install from the track's root directory I am given the message 'corepack' is not recognized as an internal or external command, operable program or batch file. (or 'pnpm' is not recognized as an internal or external command, operable program or batch file. , in the case of pnpm)

Can you try node -v. It should say 22.x.y or 20.x.y. If it says not recognised or similar, or if the version is low, you either do not have Node.JS, or it's no longer supported. In that case go to Node.js and press the download button, install, then restart your computer / open a new terminal. Try node -v again.

Once that works, continue :)

[quintuple-mallard]

All tests (both configlet and corepack pnpm node) are now passing.
It seems that .gitignore, .npmrc, LICENSE, package.json, jest.config.js, global.d.ts, eslint.config.mjs, and babel.config.js are the same across exercises, should I go ahead and add them?

[quintuple-mallard]

Is there anything else I should add or improve, or does it look good?

[kotp]

@SleeplessByte Thanks! I finally got it to work, and now the linting checks are passing.

This link is at least not public, if no good, and the image is probably text, so why not show text? Otherwise (and if you are keeping it from me, that is fine too!) how do you read this image? I had to get around the link, capture the image, tweak it, run it through my OCR. Would have been much less work as text. (Oh, bad news, you were not able to keep it from me, you just made me work for it!)

[quintuple-mallard]

@SleeplessByte Thanks! I finally got it to work, and now the linting checks are passing.

This link is at least not public, if no good, and the image is probably text, so why not show text? Otherwise (and if you are keeping it from me, that is fine too!) how do you read this image? I had to get around the link, capture the image, tweak it, run it through my OCR. Would have been much less work as text. (Oh, bad news, you were not able to keep it from me, you just made me work for it!)

Sorry!
I've changed it to text now.

[kotp]

Sorry!
I've changed it to text now.

Thanks. Hopefully the image did not leak the obfuscated information in the text version. I might never know. ;)

[SleeplessByte]

All tests (both configlet and corepack pnpm node) are now passing. It seems that .gitignore, .npmrc, LICENSE, package.json, jest.config.js, global.d.ts, eslint.config.mjs, and babel.config.js are the same across exercises, should I go ahead and add them?

If you work on another exercise, we have:

corepack pnpm node scripts/sync.mjs

[github-actions]

The "Sync all exercises" action has started running.

[SleeplessByte]

This is great and good to go. I rewrote some of the parts to be more in line with how we teach things in this track but overal really great stuff @quintuple-mallard . Appreciate you took this on and brought it to completion.

I'll batch all the changes, and then merge it. Should be live in minutes. I'll write a post announcing the new exercise.

[SleeplessByte]

[warn] concepts/randomness/about.md
[warn] concepts/randomness/introduction.md
[warn] exercises/concept/captains-log/.docs/introduction.md
[warn] exercises/concept/captains-log/.meta/exemplar.js
[warn] Code style issues found in 4 files. Run Prettier with --write to fix.

This is me. Will fix with a format locally.

[SleeplessByte]

We're live.

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I wrote a cheesy site update that will become visible... whenever it does. I don't know how long it takes to refresh. It will look something like: