Rational numbers

typescript/rational-numbers/.eslintignore

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+!.meta
+
+# Protected or generated
+.git
+.vscode
+
+# When using npm
+node_modules/*
+
+# Configuration files
+.eslintrc.cjs
+babel.config.cjs
+jest.config.cjs

typescript/rational-numbers/.eslintrc.cjs

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+module.exports = {
+  root: true,
+  parserOptions: {
+    tsconfigRootDir: __dirname,
+    project: ['./tsconfig.json'],
+  },
+  overrides: [
+    // Student provided files
+    {
+      files: ['*.ts'],
+      excludedFiles: ['.meta/proof.ci.ts', '.meta/exemplar.ts', '*.test.ts'],
+      extends: '@exercism/eslint-config-typescript',
+    },
+    // Exercism given tests
+    {
+      files: ['*.test.ts'],
+      excludedFiles: ['custom.test.ts'],
+      env: {
+        jest: true,
+      },
+      extends: '@exercism/eslint-config-typescript/maintainers',
+    },
+    // Student provided tests
+    {
+      files: ['custom.test.ts'],
+      env: {
+        jest: true,
+      },
+      extends: '@exercism/eslint-config-typescript',
+    },
+    // Exercism provided files
+    {
+      files: ['.meta/proof.ci.ts', '.meta/exemplar.ts', '*.test.ts'],
+      excludedFiles: ['custom.test.ts'],
+      extends: '@exercism/eslint-config-typescript/maintainers',
+      rules: {
+        "@typescript-eslint/semi": 0,
+      },
+    },
+  ],
+}

typescript/rational-numbers/.exercism/config.json

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+{
+  "blurb": "Implement rational numbers.",
+  "authors": ["CRivasGomez"],
+  "contributors": ["masters3d", "SleeplessByte"],
+  "files": {
+    "solution": ["rational-numbers.ts"],
+    "test": ["rational-numbers.test.ts"],
+    "example": [".meta/proof.ci.ts"]
+  },
+  "source": "Wikipedia",
+  "source_url": "https://en.wikipedia.org/wiki/Rational_number"
+}

typescript/rational-numbers/.exercism/metadata.json

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+{"track":"typescript","exercise":"rational-numbers","id":"9080cb32b0404fe18481d2b6cf5f37a5","url":"https://exercism.org/tracks/typescript/exercises/rational-numbers","handle":"briemens","is_requester":true,"auto_approve":false}

typescript/rational-numbers/HELP.md

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+# Help
+
+## Running the tests
+
+Execute the tests with:
+
+```bash
+$ 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`.
+
+## Submitting your solution
+
+You can submit your solution using the `exercism submit rational-numbers.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)
+- [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/rational-numbers/README.md

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+# Rational Numbers
+
+Welcome to Rational Numbers on Exercism's TypeScript Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+
+## Instructions
+
+A rational number is defined as the quotient of two integers `a` and `b`, called the numerator and denominator, respectively, where `b != 0`.
+
+The absolute value `|r|` of the rational number `r = a/b` is equal to `|a|/|b|`.
+
+The sum of two rational numbers `r₁ = a₁/b₁` and `r₂ = a₂/b₂` is `r₁ + r₂ = a₁/b₁ + a₂/b₂ = (a₁ * b₂ + a₂ * b₁) / (b₁ * b₂)`.
+
+The difference of two rational numbers `r₁ = a₁/b₁` and `r₂ = a₂/b₂` is `r₁ - r₂ = a₁/b₁ - a₂/b₂ = (a₁ * b₂ - a₂ * b₁) / (b₁ * b₂)`.
+
+The product (multiplication) of two rational numbers `r₁ = a₁/b₁` and `r₂ = a₂/b₂` is `r₁ * r₂ = (a₁ * a₂) / (b₁ * b₂)`.
+
+Dividing a rational number `r₁ = a₁/b₁` by another `r₂ = a₂/b₂` is `r₁ / r₂ = (a₁ * b₂) / (a₂ * b₁)` if `a₂` is not zero.
+
+Exponentiation of a rational number `r = a/b` to a non-negative integer power `n` is `r^n = (a^n)/(b^n)`.
+
+Exponentiation of a rational number `r = a/b` to a negative integer power `n` is `r^n = (b^m)/(a^m)`, where `m = |n|`.
+
+Exponentiation of a rational number `r = a/b` to a real (floating-point) number `x` is the quotient `(a^x)/(b^x)`, which is a real number.
+
+Exponentiation of a real number `x` to a rational number `r = a/b` is `x^(a/b) = root(x^a, b)`, where `root(p, q)` is the `q`th root of `p`.
+
+Implement the following operations:
+
+- addition, subtraction, multiplication and division of two rational numbers,
+- absolute value, exponentiation of a given rational number to an integer power, exponentiation of a given rational number to a real (floating-point) power, exponentiation of a real number to a rational number.
+
+Your implementation of rational numbers should always be reduced to lowest terms. For example, `4/4` should reduce to `1/1`, `30/60` should reduce to `1/2`, `12/8` should reduce to `3/2`, etc. To reduce a rational number `r = a/b`, divide `a` and `b` by the greatest common divisor (gcd) of `a` and `b`. So, for example, `gcd(12, 8) = 4`, so `r = 12/8` can be reduced to `(12/4)/(8/4) = 3/2`.
+
+Assume that the programming language you are using does not have an implementation of rational numbers.
+
+## Source
+
+### Created by
+
+- @CRivasGomez
+
+### Contributed to by
+
+- @masters3d
+- @SleeplessByte
+
+### Based on
+
+Wikipedia - https://en.wikipedia.org/wiki/Rational_number

typescript/rational-numbers/babel.config.cjs

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+module.exports = {
+  presets: ['@exercism/babel-preset-typescript'],
+  plugins: [],
+}

typescript/rational-numbers/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',
+  },
+}

typescript/rational-numbers/package.json

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+{
+  "name": "@exercism/typescript-rational-numbers",
+  "version": "1.0.0",
+  "description": "Exercism exercises in Typescript.",
+  "private": true,
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/exercism/typescript"
+  },
+  "type": "module",
+  "engines": {
+    "node": "^14.13.1 || >=16.0.0"
+  },
+  "devDependencies": {
+    "@exercism/babel-preset-typescript": "^0.1.0",
+    "@exercism/eslint-config-typescript": "^0.4.1",
+    "@types/jest": "^27.4.0",
+    "@types/node": "^16.11.24",
+    "babel-jest": "^27.5.1",
+    "core-js": "^3.21.0",
+    "eslint": "^8.9.0",
+    "jest": "^27.5.1",
+    "typescript": "^4.5.4"
+  },
+  "scripts": {
+    "test": "yarn lint:types && jest --no-cache",
+    "lint": "yarn lint:types && yarn lint:ci",
+    "lint:types": "yarn tsc --noEmit -p .",
+    "lint:ci": "eslint . --ext .tsx,.ts"
+  }
+}

typescript/rational-numbers/rational-numbers.test.ts

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+import { Rational } from "./rational-numbers";
+
+describe("Addition", () => {
+  it("Add two positive rational numbers", () => {
+    const expected = new Rational(7, 6);
+    expect(new Rational(1, 2).add(new Rational(2, 3))).toEqual(expected);
+  });
+
+  it("Add a positive rational number and a negative rational number", () => {
+    const expected = new Rational(-1, 6);
+    expect(new Rational(1, 2).add(new Rational(-2, 3))).toEqual(expected);
+  });
+
+  it("Add two negative rational numbers", () => {
+    const expected = new Rational(-7, 6);
+    expect(new Rational(-1, 2).add(new Rational(-2, 3))).toEqual(expected);
+  });
+
+  it("Add a rational number to its additive inverse", () => {
+    const expected = new Rational(0, 1);
+    expect(new Rational(1, 2).add(new Rational(-1, 2))).toEqual(expected);
+  });
+});
+
+describe("Subtraction", () => {
+  xit("Subtract two positive rational numbers", () => {
+    const expected = new Rational(-1, 6);
+    expect(new Rational(1, 2).sub(new Rational(2, 3))).toEqual(expected);
+  });
+
+  xit("Subtract a positive rational number and a negative rational number", () => {
+    const expected = new Rational(7, 6);
+    expect(new Rational(1, 2).sub(new Rational(-2, 3))).toEqual(expected);
+  });
+
+  xit("Subtract two negative rational numbers", () => {
+    const expected = new Rational(1, 6);
+    expect(new Rational(-1, 2).sub(new Rational(-2, 3))).toEqual(expected);
+  });
+
+  xit("Subtract a rational number from itself", () => {
+    const expected = new Rational(0, 1);
+    expect(new Rational(1, 2).sub(new Rational(1, 2))).toEqual(expected);
+  });
+});
+
+describe("Multiplication", () => {
+  xit("Multiply two positive rational numbers", () => {
+    const expected = new Rational(1, 3);
+    expect(new Rational(1, 2).mul(new Rational(2, 3))).toEqual(expected);
+  });
+
+  xit("Multiply a negative rational number by a positive rational number", () => {
+    const expected = new Rational(-1, 3);
+    expect(new Rational(-1, 2).mul(new Rational(2, 3))).toEqual(expected);
+  });
+
+  xit("Multiply two negative rational numbers", () => {
+    const expected = new Rational(1, 3);
+    expect(new Rational(-1, 2).mul(new Rational(-2, 3))).toEqual(expected);
+  });
+
+  xit("Multiply a rational number by its reciprocal", () => {
+    const expected = new Rational(1, 1);
+    expect(new Rational(1, 2).mul(new Rational(2, 1))).toEqual(expected);
+  });
+
+  xit("Multiply a rational number by 1", () => {
+    const expected = new Rational(1, 2);
+    expect(new Rational(1, 2).mul(new Rational(1, 1))).toEqual(expected);
+  });
+
+  xit("Multiply a rational number by 0", () => {
+    const expected = new Rational(0, 1);
+    expect(new Rational(1, 2).mul(new Rational(0, 1))).toEqual(expected);
+  });
+});
+
+describe("Division", () => {
+  xit("Divide two positive rational numbers", () => {
+    const expected = new Rational(3, 4);
+    expect(new Rational(1, 2).div(new Rational(2, 3))).toEqual(expected);
+  });
+
+  xit("Divide a positive rational number by a negative rational number", () => {
+    const expected = new Rational(-3, 4);
+    expect(new Rational(1, 2).div(new Rational(-2, 3))).toEqual(expected);
+  });
+
+  xit("Divide two negative rational numbers", () => {
+    const expected = new Rational(3, 4);
+    expect(new Rational(-1, 2).div(new Rational(-2, 3))).toEqual(expected);
+  });
+
+  xit("Divide a rational number by 1", () => {
+    const expected = new Rational(1, 2);
+    expect(new Rational(1, 2).div(new Rational(1, 1))).toEqual(expected);
+  });
+});
+
+describe("Absolute value", () => {
+  xit("Absolute value of a positive rational number", () => {
+    const expected = new Rational(1, 2);
+    expect(new Rational(1, 2).abs()).toEqual(expected);
+  });
+
+  xit("Absolute value of a negative rational number", () => {
+    const expected = new Rational(1, 2);
+    expect(new Rational(-1, 2).abs()).toEqual(expected);
+  });
+
+  xit("Absolute value of zero", () => {
+    const expected = new Rational(0, 1);
+    expect(new Rational(0, 1).abs()).toEqual(expected);
+  });
+});
+
+describe("Exponentiation of a rational number", () => {
+  xit("Raise a positive rational number to a positive integer power", () => {
+    const expected = new Rational(1, 8);
+    expect(new Rational(1, 2).exprational(3)).toEqual(expected);
+  });
+
+  xit("Raise a negative rational number to a positive integer power", () => {
+    const expected = new Rational(-1, 8);
+    expect(new Rational(-1, 2).exprational(3)).toEqual(expected);
+  });
+
+  xit("Raise zero to an integer power", () => {
+    const expected = new Rational(0, 1);
+    expect(new Rational(0, 1).exprational(5)).toEqual(expected);
+  });
+
+  xit("Raise one to an integer power", () => {
+    const expected = new Rational(1, 1);
+    expect(new Rational(1, 1).exprational(4)).toEqual(expected);
+  });
+
+  xit("Raise a positive rational number to the power of zero", () => {
+    const expected = new Rational(1, 1);
+    expect(new Rational(1, 2).exprational(0)).toEqual(expected);
+  });
+
+  xit("Raise a negative rational number to the power of zero", () => {
+    const expected = new Rational(1, 1);
+    expect(new Rational(-1, 2).exprational(0)).toEqual(expected);
+  });
+});
+
+describe("Exponentiation of a real number to a rational number", () => {
+  xit("Raise a real number to a positive rational number", () => {
+    const expected = 16.0;
+    expect(new Rational(4, 3).expreal(8)).toEqual(expected);
+  });
+
+  xit("Raise a real number to a negative rational number", () => {
+    const expected = 1.0 / 3.0;
+    expect(new Rational(-1, 2).expreal(9)).toBeCloseTo(expected, 15);
+  });
+
+  xit("Raise a real number to a zero rational number", () => {
+    const expected = 1.0;
+    expect(new Rational(0, 1).expreal(2)).toEqual(expected);
+  });
+});
+
+describe("Reduction to lowest terms", () => {
+  xit("Reduce a positive rational number to lowest terms", () => {
+    const expected = new Rational(1, 2);
+    expect(new Rational(2, 4).reduce()).toEqual(expected);
+  });
+
+  xit("Reduce a negative rational number to lowest terms", () => {
+    const expected = new Rational(-2, 3);
+    expect(new Rational(-4, 6).reduce()).toEqual(expected);
+  });
+
+  xit("Reduce a rational number with a negative denominator to lowest terms", () => {
+    const expected = new Rational(-1, 3);
+    expect(new Rational(3, -9).reduce()).toEqual(expected);
+  });
+
+  xit("Reduce zero to lowest terms", () => {
+    const expected = new Rational(0, 1);
+    expect(new Rational(0, 6).reduce()).toEqual(expected);
+  });
+
+  xit("Reduce an integer to lowest terms", () => {
+    const expected = new Rational(-2, 1);
+    expect(new Rational(-14, 7).reduce()).toEqual(expected);
+  });
+
+  xit("Reduce one to lowest terms", () => {
+    const expected = new Rational(1, 1);
+    expect(new Rational(13, 13).reduce()).toEqual(expected);
+  });
+});

typescript/rational-numbers/rational-numbers.ts

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+function isPrime(n: number): boolean {
+  if (n === 2) {
+    return true;
+  }
+  if (n < 2 || n % 2 === 0) {
+    return false;
+  }
+  for (var i = 3; i <= Math.sqrt(n); i += 2) {
+    if (n % i === 0) {
+      return false;
+    }
+  }
+  return true;
+}
+
+function* primes(): Generator<number> {
+  let i = 0;
+  while (true) {
+    if (!isPrime(i)) {
+      i++;
+      continue;
+    }
+    yield i++;
+  }
+}
+
+for (let prime of primes()) {
+  console.log("prime", prime);
+  if (prime > 1000) {
+    break;
+  }
+}
+
+export class Rational {
+  constructor(public numerator: number, public denominator: number) {
+    if (denominator < 0) {
+      this.numerator = numerator * -1;
+      this.denominator = denominator;
+    }
+  }
+
+  add(rational: Rational): Rational {
+    /* The sum of two rational numbers `r₁ = a₁/b₁` and `r₂ = a₂/b₂`
+     * is `r₁ + r₂ = a₁/b₁ + a₂/b₂ = (a₁ * b₂ + a₂ * b₁) / (b₁ * b₂)`. */
+    return new Rational(
+      this.numerator * rational.denominator +
+        this.denominator * rational.numerator,
+      rational.numerator * rational.denominator
+    );
+  }
+
+  sub(rational: Rational): Rational {
+    throw new Error("Remove this statement and implement this function");
+  }
+
+  mul(rational: Rational): Rational {
+    throw new Error("Remove this statement and implement this function");
+  }
+
+  div(rational: Rational): Rational {
+    throw new Error("Remove this statement and implement this function");
+  }
+
+  abs(): Rational {
+    throw new Error("Remove this statement and implement this function");
+  }
+
+  exprational(amount: number): Rational {
+    throw new Error("Remove this statement and implement this function");
+  }
+
+  expreal(amount: number): Rational {
+    throw new Error("Remove this statement and implement this function");
+  }
+
+  reduce(): Rational {
+    throw new Error("Remove this statement and implement this function");
+  }
+}

typescript/rational-numbers/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": ["ESNEXT", "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": "ES2020",
+    // 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": "ESNext", // ESLint doesn't support this yet: "es2022",
+
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": 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"],
+  "exclude": ["node_modules"]
+}