Multiple exercises were added to the TypeScript track in this commit.

typescript/collatz-conjecture/.exercism/config.json

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+{
+  "authors": [
+    "CRivasGomez"
+  ],
+  "contributors": [
+    "masters3d",
+    "SleeplessByte"
+  ],
+  "files": {
+    "solution": [
+      "collatz-conjecture.ts"
+    ],
+    "test": [
+      "collatz-conjecture.test.ts"
+    ],
+    "example": [
+      ".meta/proof.ci.ts"
+    ]
+  },
+  "blurb": "Calculate the number of steps to reach 1 using the Collatz conjecture",
+  "custom": {
+    "version.tests.compatibility": "jest-29",
+    "flag.tests.task-per-describe": false,
+    "flag.tests.may-run-long": false,
+    "flag.tests.includes-optional": false,
+    "flag.tests.jest": true,
+    "flag.tests.tstyche": false
+  },
+  "source": "An unsolved problem in mathematics named after mathematician Lothar Collatz",
+  "source_url": "https://en.wikipedia.org/wiki/3x_%2B_1_problem"
+}

typescript/collatz-conjecture/.exercism/metadata.json

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+{"track":"typescript","exercise":"collatz-conjecture","id":"6573b4612c77440bb14a040ef214e448","url":"https://exercism.org/tracks/typescript/exercises/collatz-conjecture","handle":"briemens","is_requester":true,"auto_approve":false}

typescript/collatz-conjecture/.vscode/extensions.json

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+{
+  "recommendations": [
+    "arcanis.vscode-zipfs",
+    "dbaeumer.vscode-eslint",
+    "esbenp.prettier-vscode"
+  ]
+}

typescript/collatz-conjecture/.vscode/settings.json

@@ -0,0 +1,7 @@
+{
+  "cSpell.words": ["exercism"],
+  "search.exclude": {
+    "**/.yarn": true,
+    "**/.pnp.*": true
+  }
+}

typescript/collatz-conjecture/.yarnrc.yml

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+compressionLevel: mixed
+
+enableGlobalCache: true

typescript/collatz-conjecture/HELP.md

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+# Help
+
+## Running the tests
+
+Before trying to execute the tests, ensure the assignment folder is set-up correctly by following the installation steps, namely `corepack yarn install` and the Editor SDK setup.
+
+Execute the tests with:
+
+```bash
+$ corepack yarn test
+```
+
+## Skipped tests
+
+In the test suites all tests but the first have been skipped.
+
+Once you get a test passing, you can enable the next one by changing `xit` to `it`.
+Additionally tests may be grouped using `xdescribe`.
+Enable the group by changing that to `describe`.
+Finally, some exercises may have optional tests `it.skip`.
+Remove `.skip` to execute the optional test.
+
+## Submitting your solution
+
+You can submit your solution using the `exercism submit collatz-conjecture.ts` command.
+This command will upload your solution to the Exercism website and print the solution page's URL.
+
+It's possible to submit an incomplete solution which allows you to:
+
+- See how others have completed the exercise
+- Request help from a mentor
+
+## Need to get help?
+
+If you'd like help solving the exercise, check the following pages:
+
+- The [TypeScript track's documentation](https://exercism.org/docs/tracks/typescript)
+- The [TypeScript track's programming category on the forum](https://forum.exercism.org/c/programming/typescript)
+- [Exercism's programming category on the forum](https://forum.exercism.org/c/programming/5)
+- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs)
+
+Should those resources not suffice, you could submit your (incomplete) solution to request mentoring.
+
+To get help if you're having trouble, you can use one of the following resources:
+
+- [TypeScript QuickStart](https://www.typescriptlang.org/docs/handbook/release-notes/overview.html)
+- [ECMAScript 2015 Language Specification](https://www.ecma-international.org/wp-content/uploads/ECMA-262_6th_edition_june_2015.pdf) (pdf)
+- [Mozilla JavaScript Reference](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference)
+- [/r/typescript](https://www.reddit.com/r/typescript) is the TypeScript subreddit.
+- [StackOverflow](https://stackoverflow.com/questions/tagged/typescript) can be used to search for your problem and see if it has been answered already. You can also ask and answer questions.

typescript/collatz-conjecture/README.md

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+# Collatz Conjecture
+
+Welcome to Collatz Conjecture on Exercism's TypeScript Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+
+## Instructions
+
+The Collatz Conjecture or 3x+1 problem can be summarized as follows:
+
+Take any positive integer n.
+If n is even, divide n by 2 to get n / 2.
+If n is odd, multiply n by 3 and add 1 to get 3n + 1.
+Repeat the process indefinitely.
+The conjecture states that no matter which number you start with, you will always reach 1 eventually.
+
+Given a number n, return the number of steps required to reach 1.
+
+## Examples
+
+Starting with n = 12, the steps would be as follows:
+
+0. 12
+1. 6
+2. 3
+3. 10
+4. 5
+5. 16
+6. 8
+7. 4
+8. 2
+9. 1
+
+Resulting in 9 steps.
+So for input n = 12, the return value would be 9.
+
+## Source
+
+### Created by
+
+- @CRivasGomez
+
+### Contributed to by
+
+- @masters3d
+- @SleeplessByte
+
+### Based on
+
+An unsolved problem in mathematics named after mathematician Lothar Collatz - https://en.wikipedia.org/wiki/3x_%2B_1_problem

typescript/collatz-conjecture/babel.config.cjs

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+module.exports = {
+  // eslint-disable-next-line @typescript-eslint/no-require-imports
+  presets: [[require('@exercism/babel-preset-typescript'), { corejs: '3.38' }]],
+  plugins: [],
+}

typescript/collatz-conjecture/collatz-conjecture.test.ts

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+import { describe, it, expect, xit } from '@jest/globals'
+import { steps } from './collatz-conjecture.ts'
+
+describe('CollatzConjecture', () => {
+  it('zero steps for one', () => {
+    const expected = 0
+    expect(steps(1)).toBe(expected)
+  })
+
+  it('divide if even', () => {
+    const expected = 4
+    expect(steps(16)).toBe(expected)
+  })
+
+  it('even and odd steps', () => {
+    const expected = 9
+    expect(steps(12)).toBe(expected)
+  })
+
+  it('Large number of even and odd steps', () => {
+    const expected = 152
+    expect(steps(1000000)).toBe(expected)
+  })
+
+  it('zero is an error', () => {
+    const expected = 'Only positive integers are allowed'
+    expect(() => {
+      steps(0)
+    }).toThrow(expected)
+  })
+
+  it('negative value is an error', () => {
+    const expected = 'Only positive integers are allowed'
+    expect(() => {
+      steps(-15)
+    }).toThrow(expected)
+  })
+
+  it('non-integer value is an error', () => {
+    const expected = 'Only positive integers are allowed'
+    expect(() => {
+      steps(3.1415)
+    }).toThrow(expected)
+  })
+})

typescript/collatz-conjecture/collatz-conjecture.ts

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+function step(count: number, interation: number): number {
+  if (count === 1) return interation
+  if (count % 2 === 0) { // Even
+    return step(count / 2, interation + 1)
+  } else {
+    return step((3 * count) + 1, interation + 1)
+  }
+}
+
+export function steps(count: number): number {
+  if (!count || count < 1 || Math.trunc(count) !== count)
+    throw new Error('Only positive integers are allowed')
+  return step(count, 0)
+}

typescript/collatz-conjecture/eslint.config.mjs

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+// @ts-check
+
+import tsEslint from 'typescript-eslint'
+import config from '@exercism/eslint-config-typescript'
+import maintainersConfig from '@exercism/eslint-config-typescript/maintainers.mjs'
+
+export default [
+  ...tsEslint.config(...config, {
+    files: ['.meta/proof.ci.ts', '.meta/exemplar.ts', '*.test.ts'],
+    extends: maintainersConfig,
+  }),
+  {
+    ignores: [
+      // # Protected or generated
+      '.git/**/*',
+      '.vscode/**/*',
+
+      //# When using npm
+      'node_modules/**/*',
+
+      // # Configuration files
+      'babel.config.cjs',
+      'jest.config.cjs',
+    ],
+  },
+]

typescript/collatz-conjecture/jest.config.cjs

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+module.exports = {
+  verbose: true,
+  projects: ['<rootDir>'],
+  testMatch: [
+    '**/__tests__/**/*.[jt]s?(x)',
+    '**/test/**/*.[jt]s?(x)',
+    '**/?(*.)+(spec|test).[jt]s?(x)',
+  ],
+  testPathIgnorePatterns: [
+    '/(?:production_)?node_modules/',
+    '.d.ts$',
+    '<rootDir>/test/fixtures',
+    '<rootDir>/test/helpers',
+    '__mocks__',
+  ],
+  transform: {
+    '^.+\\.[jt]sx?$': 'babel-jest',
+  },
+  moduleNameMapper: {
+    '^(\\.\\/.+)\\.js$': '$1',
+  },
+}

typescript/collatz-conjecture/package.json

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+{
+  "name": "@exercism/typescript-collatz-conjecture",
+  "version": "1.0.0",
+  "description": "Exercism exercises in Typescript.",
+  "private": true,
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/exercism/typescript"
+  },
+  "type": "module",
+  "engines": {
+    "node": "^18.16.0 || >=20.0.0"
+  },
+  "devDependencies": {
+    "@exercism/babel-preset-typescript": "^0.6.0",
+    "@exercism/eslint-config-typescript": "^0.8.0",
+    "@jest/globals": "^29.7.0",
+    "@types/node": "~22.7.6",
+    "babel-jest": "^29.7.0",
+    "core-js": "~3.38.1",
+    "eslint": "^9.12.0",
+    "expect": "^29.7.0",
+    "jest": "^29.7.0",
+    "prettier": "^3.3.3",
+    "tstyche": "^2.1.1",
+    "typescript": "~5.6.3",
+    "typescript-eslint": "^8.10.0"
+  },
+  "scripts": {
+    "test": "corepack yarn node test-runner.mjs",
+    "test:types": "corepack yarn tstyche",
+    "test:implementation": "corepack yarn jest --no-cache --passWithNoTests",
+    "lint": "corepack yarn lint:types && corepack yarn lint:ci",
+    "lint:types": "corepack yarn tsc --noEmit -p .",
+    "lint:ci": "corepack yarn eslint . --ext .tsx,.ts"
+  },
+  "packageManager": "yarn@4.5.1"
+}

typescript/collatz-conjecture/test-runner.mjs

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+#!/usr/bin/env node
+
+/**
+ * 👋🏽 Hello there reader,
+ *
+ * It looks like you are working on this solution using the Exercism CLI and
+ * not the online editor. That's great! The file you are looking at executes
+ * the various steps the online test-runner also takes.
+ *
+ * @see https://github.com/exercism/typescript-test-runner
+ *
+ * TypeScript track exercises generally consist of at least two out of three
+ * types of tests to run.
+ *
+ * 1. tsc, the TypeScript compiler. This tests if the TypeScript code is valid
+ * 2. tstyche, static analysis tests to see if the types used are expected
+ * 3. jest, runtime implementation tests to see if the solution is correct
+ *
+ * If one of these three fails, this script terminates with -1, -2, or -3
+ * respectively. If it succeeds, it terminates with exit code 0.
+ *
+ * @note you need corepack (bundled with node LTS) enabled in order for this
+ *    test runner to work as expected. Follow the installation and test
+ *    instructions if you see errors about corepack or pnp.
+ */
+
+import { execSync } from 'node:child_process'
+import { existsSync, readFileSync } from 'node:fs'
+import { exit } from 'node:process'
+import { URL } from 'node:url'
+
+/**
+ * Before executing any tests, the test runner attempts to find the
+ * exercise config.json file which has metadata about which types of tests
+ * to run for this solution.
+ */
+const metaDirectory = new URL('./.meta/', import.meta.url)
+const exercismDirectory = new URL('./.exercism/', import.meta.url)
+const configDirectory = existsSync(metaDirectory)
+  ? metaDirectory
+  : existsSync(exercismDirectory)
+    ? exercismDirectory
+    : null
+
+if (configDirectory === null) {
+  throw new Error(
+    'Expected .meta or .exercism directory to exist, but I cannot find it.'
+  )
+}
+
+const configFile = new URL('./config.json', configDirectory)
+if (!existsSync(configFile)) {
+  throw new Error('Expected config.json to exist at ' + configFile.toString())
+}
+
+// Experimental: import config from './config.json' with { type: 'json' }
+/** @type {import('./config.json') } */
+const config = JSON.parse(readFileSync(configFile))
+
+const jest = !config.custom || config.custom['flag.tests.jest']
+const tstyche = config.custom?.['flag.tests.tstyche']
+console.log(
+  `[tests] tsc: ✅, tstyche: ${tstyche ? '✅' : '❌'}, jest: ${jest ? '✅' : '❌'}, `
+)
+
+/**
+ * 1. tsc: the typescript compiler
+ */
+try {
+  console.log('[tests] tsc (compile)')
+  execSync('corepack yarn lint:types', {
+    stdio: 'inherit',
+    cwd: process.cwd(),
+  })
+} catch {
+  exit(-1)
+}
+
+/**
+ * 2. tstyche: type tests
+ */
+if (tstyche) {
+  try {
+    console.log('[tests] tstyche (type tests)')
+    execSync('corepack yarn test:types', {
+      stdio: 'inherit',
+      cwd: process.cwd(),
+    })
+  } catch {
+    exit(-2)
+  }
+}
+
+/**
+ * 3. jest: implementation tests
+ */
+if (jest) {
+  try {
+    console.log('[tests] tstyche (implementation tests)')
+    execSync('corepack yarn test:implementation', {
+      stdio: 'inherit',
+      cwd: process.cwd(),
+    })
+  } catch {
+    exit(-3)
+  }
+}
+
+/**
+ * Done! 🥳
+ */

typescript/collatz-conjecture/tsconfig.json

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+{
+  "display": "Configuration for Exercism TypeScript Exercises",
+  "compilerOptions": {
+    // Allows you to use the newest syntax, and have access to console.log
+    // https://www.typescriptlang.org/tsconfig#lib
+    "lib": ["ES2020", "dom"],
+    // Make sure typescript is configured to output ESM
+    // https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c#how-can-i-make-my-typescript-project-output-esm
+    "module": "Node16",
+    // Since this project is using babel, TypeScript may target something very
+    // high, and babel will make sure it runs on your local Node version.
+    // https://babeljs.io/docs/en/
+    "target": "ES2020", // ESLint doesn't support this yet: "es2022",
+
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+
+    // Because jest-resolve isn't like node resolve, the absolute path must be .ts
+    "allowImportingTsExtensions": true,
+    "noEmit": true,
+
+    // Because we'll be using babel: ensure that Babel can safely transpile
+    // files in the TypeScript project.
+    //
+    // https://babeljs.io/docs/en/babel-plugin-transform-typescript/#caveats
+    "isolatedModules": true
+  },
+  "include": [
+    "*.ts",
+    "*.tsx",
+    ".meta/*.ts",
+    ".meta/*.tsx",
+    "__typetests__/*.tst.ts"
+  ],
+  "exclude": ["node_modules"]
+}