Initial commit

Author: mattpocock

.gitignore

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+node_modules

.vscode/settings.json

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+{
+  "window.zoomLevel": 3,
+  "editor.formatOnSave": true,
+  "editor.tabSize": 2,
+  "explorer.autoReveal": false,
+  "workbench.statusBar.visible": false,
+  "workbench.activityBar.visible": false,
+  "workbench.editor.showTabs": false,
+  "breadcrumbs.enabled": true,
+  "editor.minimap.enabled": false,
+  "workbench.sideBar.location": "right",
+  "git.enableSmartCommit": true,
+  "editor.lineNumbers": "off",
+  "editor.folding": false,
+  "editor.defaultFormatter": "esbenp.prettier-vscode",
+  "editor.inlineSuggest.enabled": true,
+  "xstate.targetEditorBaseUrl": "http://localhost:3000",
+}

README.md

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+# Zod Crash Course
+
+This Zod crash course will give you everything you ever needed to know about [Zod](https://github.com/colinhacks/zod) - an amazing library for building type-safe AND runtime-safe applications.
+
+## Quickstart
+
+```sh
+# Installs all dependencies
+yarn install
+
+# Starts the first exercise
+yarn exercise 01
+```
+
+## How to take the course
+
+First, start up the [video on YouTube](TODO).
+
+You'll notice that the course is split into exercises. Each exercise is split into a `*.problem.ts` and a `*.solution.ts`.
+
+To take an exercise:
+
+1. Go into `*.problem.ts`
+2. Run `yarn exercise 01`, where `01` is the number of the exercise you're on.
+
+The `exercise` script will run TypeScript typechecks and a test suite on the exercise.
+
+This course encourages **active, exploratory learning**. In the video, I'll explain a problem, and **you'll be asked to try to find a solution**. To attempt a solution, you'll need to:
+
+1. Check out [Zod's docs](https://github.com/colinhacks/zod)
+2. Try to find something that looks relevant.
+3. Give it a go to see if it solves the problem.
+
+You'll know if you've succeeded because the tests will pass.
+
+**If you succeeed**, or **if you get stuck**, unpause the video and check out the `*.solution.ts`. You can see if your solution is better or worse than mine!
+
+## Acknowledgements
+
+Say thanks to Matt on [Twitter](https://twitter.com/mattpocockuk) or by joining his [Discord](https://discord.gg/8S5ujhfTB3). Consider signing up to his [Total TypeScript course](https://totaltypescript.com).

package.json

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+{
+  "name": "beginners",
+  "version": "1.0.0",
+  "main": "index.js",
+  "author": "Matt Pocock <[email protected]>",
+  "license": "MIT",
+  "devDependencies": {
+    "@types/node": "^18.6.5",
+    "chokidar": "^3.5.3",
+    "cross-fetch": "^3.1.5",
+    "typescript": "^4.7.4",
+    "vitest": "^0.21.1"
+  },
+  "scripts": {
+    "exercise": "node scripts/exercise.js",
+    "solution": "SOLUTION=true node scripts/exercise.js"
+  },
+  "dependencies": {
+    "@types/express": "^4.17.13",
+    "express": "^4.18.1",
+    "zod": "^3.17.10"
+  }
+}

scripts/exercise.js

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+const { execSync } = require("child_process");
+const fs = require("fs");
+const path = require("path");
+const chokidar = require("chokidar");
+
+const srcPath = path.resolve(__dirname, "../src");
+const tsconfigPath = path.resolve(__dirname, "../tsconfig.json");
+
+const [, , exercise] = process.argv;
+
+if (!exercise) {
+  console.log("Please specify an exercise");
+  process.exit(1);
+}
+
+const allExercises = fs.readdirSync(srcPath);
+
+let suffix = ".problem.ts";
+
+if (process.env.SOLUTION) {
+  suffix = ".solution.ts";
+}
+
+const exercisePath = allExercises.find(
+  (exercisePath) =>
+    exercisePath.startsWith(exercise) && exercisePath.endsWith(suffix),
+);
+
+if (!exercisePath) {
+  console.log(`Exercise ${exercise} not found`);
+  process.exit(1);
+}
+
+const exerciseFile = path.resolve(srcPath, exercisePath);
+
+// One-liner for current directory
+chokidar.watch(exerciseFile).on("all", (event, path) => {
+  try {
+    console.clear();
+    console.log("Running tests...");
+    execSync(`vitest run ${exerciseFile} --passWithNoTests`, {
+      stdio: "inherit",
+    });
+    console.log("Checking types...");
+    execSync(`tsc ${exerciseFile} --noEmit --strict`, {
+      stdio: "inherit",
+    });
+    console.log("Typecheck complete. You finished the exercise!");
+  } catch (e) {
+    console.log("Failed. Try again!");
+  }
+});

scripts/setup.ts

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+import { fetch } from "cross-fetch";
+
+global.fetch = fetch;

src/01-number.problem.ts

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+import { expect, it } from "vitest";
+
+export const addTwoNumbers = (a, b) => {
+  return a + b;
+};
+
+it("Should add the two numbers together", () => {
+  expect(addTwoNumbers(2, 4)).toEqual(6);
+  expect(addTwoNumbers(10, 10)).toEqual(20);
+});

src/01-number.solution.ts

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+import { expect, it } from "vitest";
+
+export const addTwoNumbers = (a: number, b: number) => {
+  return a + b;
+};
+
+it("Should add the two numbers together", () => {
+  expect(addTwoNumbers(2, 4)).toEqual(6);
+  expect(addTwoNumbers(10, 10)).toEqual(20);
+});

src/02-object-param.problem.ts

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+import { expect, it } from "vitest";
+
+export const addTwoNumbers = (params) => {
+  return params.first + params.second;
+};
+
+it("Should add the two numbers together", () => {
+  expect(
+    addTwoNumbers({
+      first: 2,
+      second: 4,
+    }),
+  ).toEqual(6);
+
+  expect(
+    addTwoNumbers({
+      first: 10,
+      second: 20,
+    }),
+  ).toEqual(20);
+});

src/02-object-param.solution.1.ts

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+import { expect, it } from "vitest";
+
+export const addTwoNumbers = (params: { first: number; second: number }) => {
+  return params.first + params.second;
+};
+
+it("Should add the two numbers together", () => {
+  expect(
+    addTwoNumbers({
+      first: 2,
+      second: 4,
+    }),
+  ).toEqual(6);
+
+  expect(
+    addTwoNumbers({
+      first: 10,
+      second: 20,
+    }),
+  ).toEqual(20);
+});

src/02-object-param.solution.2.ts

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+import { expect, it } from "vitest";
+
+type AddTwoNumbersArgs = {
+  first: number;
+  second: number;
+};
+
+export const addTwoNumbers = (params: AddTwoNumbersArgs) => {
+  return params.first + params.second;
+};
+
+it("Should add the two numbers together", () => {
+  expect(
+    addTwoNumbers({
+      first: 2,
+      second: 4,
+    }),
+  ).toEqual(6);
+
+  expect(
+    addTwoNumbers({
+      first: 10,
+      second: 20,
+    }),
+  ).toEqual(20);
+});

src/02-object-param.solution.3.ts

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+import { expect, it } from "vitest";
+
+interface AddTwoNumbersArgs {
+  first: number;
+  second: number;
+}
+
+export const addTwoNumbers = (params: AddTwoNumbersArgs) => {
+  return params.first + params.second;
+};
+
+it("Should add the two numbers together", () => {
+  expect(
+    addTwoNumbers({
+      first: 2,
+      second: 4,
+    }),
+  ).toEqual(6);
+
+  expect(
+    addTwoNumbers({
+      first: 10,
+      second: 20,
+    }),
+  ).toEqual(20);
+});

src/03-optional-properties.problem.ts

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+import { expect, it } from "vitest";
+
+export const getName = (params: { first: string; last: string }) => {
+  if (params.last) {
+    return `${params.first} ${params.last}`;
+  }
+  return params.first;
+};
+
+it("Should work with just the first name", () => {
+  const name = getName({
+    first: "Matt",
+  });
+
+  expect(name).toEqual("Matt");
+});
+
+it("Should work with the first and last name", () => {
+  const name = getName({
+    first: "Matt",
+    last: "Pocock",
+  });
+
+  expect(name).toEqual("Matt Pocock");
+});

src/03-optional-properties.solution.ts

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+import { expect, it } from "vitest";
+
+export const getName = (params: { first: string; last?: string }) => {
+  if (params.last) {
+    return `${params.first} ${params.last}`;
+  }
+  return params.first;
+};
+
+it("Should work with just the first name", () => {
+  const name = getName({
+    first: "Matt",
+  });
+
+  expect(name).toEqual("Matt");
+});
+
+it("Should work with the first and last name", () => {
+  const name = getName({
+    first: "Matt",
+    last: "Pocock",
+  });
+
+  expect(name).toEqual("Matt Pocock");
+});

src/04-optional-params.problem.ts

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+import { expect, it } from "vitest";
+
+export const getName = (first: string, last: string) => {
+  if (last) {
+    return `${first} ${last}`;
+  }
+  return first;
+};
+
+it("Should work with just the first name", () => {
+  const name = getName("Matt");
+
+  expect(name).toEqual("Matt");
+});
+
+it("Should work with the first and last name", () => {
+  const name = getName("Matt", "Pocock");
+
+  expect(name).toEqual("Matt Pocock");
+});

src/04-optional-params.solution.ts

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+import { expect, it } from "vitest";
+
+export const getName = (first: string, last?: string) => {
+  if (last) {
+    return `${first} ${last}`;
+  }
+  return first;
+};
+
+it("Should work with just the first name", () => {
+  const name = getName("Matt");
+
+  expect(name).toEqual("Matt");
+});
+
+it("Should work with the first and last name", () => {
+  const name = getName("Matt", "Pocock");
+
+  expect(name).toEqual("Matt Pocock");
+});

src/helpers/type-utils.ts

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+export type Expect<T extends true> = T;
+export type ExpectTrue<T extends true> = T;
+export type ExpectFalse<T extends false> = T;
+export type IsTrue<T extends true> = T;
+export type IsFalse<T extends false> = T;
+
+export type Equal<X, Y> = (<T>() => T extends X ? 1 : 2) extends <
+  T,
+>() => T extends Y ? 1 : 2
+  ? true
+  : false;
+export type NotEqual<X, Y> = true extends Equal<X, Y> ? false : true;
+
+// https://stackoverflow.com/questions/49927523/disallow-call-with-any/49928360#49928360
+export type IsAny<T> = 0 extends 1 & T ? true : false;
+export type NotAny<T> = true extends IsAny<T> ? false : true;
+
+export type Debug<T> = { [K in keyof T]: T[K] };
+export type MergeInsertions<T> = T extends object
+  ? { [K in keyof T]: MergeInsertions<T[K]> }
+  : T;
+
+export type Alike<X, Y> = Equal<MergeInsertions<X>, MergeInsertions<Y>>;
+
+export type ExpectExtends<VALUE, EXPECTED> = EXPECTED extends VALUE
+  ? true
+  : false;
+export type ExpectValidArgs<
+  FUNC extends (...args: any[]) => any,
+  ARGS extends any[],
+> = ARGS extends Parameters<FUNC> ? true : false;
+
+export type UnionToIntersection<U> = (
+  U extends any ? (k: U) => void : never
+) extends (k: infer I) => void
+  ? I
+  : never;