Grade school

typescript/grade-school/.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/grade-school/.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/grade-school/.exercism/config.json

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+{
+  "blurb": "Given students' names along with the grade that they are in, create a roster for the school",
+  "authors": ["masters3d"],
+  "contributors": ["lukaszklis", "pedrorolo", "SleeplessByte"],
+  "files": {
+    "solution": ["grade-school.ts"],
+    "test": ["grade-school.test.ts"],
+    "example": [".meta/proof.ci.ts"]
+  },
+  "source": "A pairing session with Phil Battos at gSchool",
+  "source_url": "http://gschool.it"
+}

typescript/grade-school/.exercism/metadata.json

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+{"track":"typescript","exercise":"grade-school","id":"35dfa4bfea7c4bda8252d9d6099423b9","url":"https://exercism.org/tracks/typescript/exercises/grade-school","handle":"briemens","is_requester":true,"auto_approve":false}

typescript/grade-school/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 grade-school.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/grade-school/README.md

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+# Grade School
+
+Welcome to Grade School on Exercism's TypeScript Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+
+## Instructions
+
+Given students' names along with the grade that they are in, create a roster
+for the school.
+
+In the end, you should be able to:
+
+- Add a student's name to the roster for a grade
+  - "Add Jim to grade 2."
+  - "OK."
+- Get a list of all students enrolled in a grade
+  - "Which students are in grade 2?"
+  - "We've only got Jim just now."
+- Get a sorted list of all students in all grades. Grades should sort
+  as 1, 2, 3, etc., and students within a grade should be sorted
+  alphabetically by name.
+  - "Who all is enrolled in school right now?"
+  - "Let me think. We have
+    Anna, Barb, and Charlie in grade 1,
+    Alex, Peter, and Zoe in grade 2
+    and Jim in grade 5.
+    So the answer is: Anna, Barb, Charlie, Alex, Peter, Zoe and Jim"
+
+Note that all our students only have one name. (It's a small town, what
+do you want?)
+
+## For bonus points
+
+Did you get the tests passing and the code clean? If you want to, these
+are some additional things you could try:
+
+- If you're working in a language with mutable data structures and your
+  implementation allows outside code to mutate the school's internal DB
+  directly, see if you can prevent this. Feel free to introduce additional
+  tests.
+
+Then please share your thoughts in a comment on the submission. Did this
+experiment make the code better? Worse? Did you learn anything from it?
+
+## Source
+
+### Created by
+
+- @masters3d
+
+### Contributed to by
+
+- @lukaszklis
+- @pedrorolo
+- @SleeplessByte
+
+### Based on
+
+A pairing session with Phil Battos at gSchool - http://gschool.it

typescript/grade-school/babel.config.cjs

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

typescript/grade-school/grade-school.test.ts

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+import { GradeSchool } from "./grade-school";
+
+describe("School", () => {
+  let school: GradeSchool;
+
+  beforeEach(() => {
+    school = new GradeSchool();
+  });
+
+  it("a new school has an empty roster", () => {
+    expect(school.roster()).toEqual({});
+  });
+
+  it("adding a student adds them to the roster for the given grade", () => {
+    school.add("Aimee", 2);
+
+    const expectedDb = { 2: ["Aimee"] };
+    expect(school.roster()).toEqual(expectedDb);
+  });
+
+  it("adding more students to the same grade adds them to the roster", () => {
+    school.add("Blair", 2);
+    school.add("James", 2);
+    school.add("Paul", 2);
+
+    const expectedDb = { 2: ["Blair", "James", "Paul"] };
+    expect(school.roster()).toEqual(expectedDb);
+  });
+
+  it("adding students to different grades adds them to the roster", () => {
+    school.add("Chelsea", 3);
+    school.add("Logan", 7);
+
+    const expectedDb = { 3: ["Chelsea"], 7: ["Logan"] };
+    expect(school.roster()).toEqual(expectedDb);
+  });
+
+  it("grade returns the students in that grade in alphabetical order", () => {
+    school.add("Franklin", 5);
+    school.add("Bradley", 5);
+    school.add("Jeff", 1);
+
+    const expectedStudents = ["Bradley", "Franklin"];
+    expect(school.grade(5)).toEqual(expectedStudents);
+  });
+
+  it("grade returns an empty array if there are no students in that grade", () => {
+    expect(school.grade(1)).toEqual([]);
+  });
+
+  it("the students names in each grade in the roster are sorted", () => {
+    school.add("Jennifer", 4);
+    school.add("Kareem", 6);
+    school.add("Christopher", 4);
+    school.add("Kyle", 3);
+
+    const expectedSortedStudents = {
+      3: ["Kyle"],
+      4: ["Christopher", "Jennifer"],
+      6: ["Kareem"],
+    };
+    expect(school.roster()).toEqual(expectedSortedStudents);
+  });
+
+  it("roster cannot be modified outside of module", () => {
+    school.add("Aimee", 2);
+    const roster = school.roster();
+    roster[2].push("Oops.");
+    const expectedDb = { 2: ["Aimee"] };
+    expect(school.roster()).toEqual(expectedDb);
+  });
+
+  it("roster cannot be modified outside of module using grade()", () => {
+    school.add("Aimee", 2);
+    school.grade(2).push("Oops.");
+    const expectedDb = { 2: ["Aimee"] };
+    expect(school.roster()).toEqual(expectedDb);
+  });
+
+  it("a student can't be in two different grades", () => {
+    school.add("Aimee", 2);
+    school.add("Aimee", 1);
+
+    expect(school.grade(2)).toEqual([]);
+  });
+});

typescript/grade-school/grade-school.ts

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+export class GradeSchool {
+  private _roster: Record<number, string[]> = {};
+
+  roster(): Record<number, string[]> {
+    return JSON.parse(JSON.stringify(this._roster));
+  }
+
+  get grades(): number[] {
+    return Object.keys(this._roster) as unknown as number[];
+  }
+
+  add(name: string, grade: number): void {
+    const addUniqueValue = <T extends any>(
+      array: T[] | undefined,
+      value: T
+    ): T[] => [...new Set<T>([...(array || []), value])];
+
+    const allGrades = addUniqueValue(this.grades, grade);
+
+    this._roster = allGrades.reduce(
+      (newRoster, rosterGrade) => ({
+        ...newRoster,
+        [rosterGrade]:
+          rosterGrade === grade
+            ? addUniqueValue(newRoster[rosterGrade], name).sort()
+            : newRoster[rosterGrade].filter((n) => n !== name),
+      }),
+      this._roster
+    );
+  }
+
+  grade(grade: number): string[] {
+    return this.roster()[grade] || [];
+  }
+}

typescript/grade-school/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/grade-school/package.json

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+{
+  "name": "@exercism/typescript-grade-school",
+  "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/grade-school/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"]
+}