TypeScript on GitHub: 7 Repositories to Level Up Your Code

Why TypeScript is the New Standard, and Where to Find the Best Code?

If you write in JavaScript and haven't switched to TypeScript yet, you're wasting time. Seriously. TypeScript (or TS) is not just an "add-on" to JS. It's strict typing, autocompletion, refactoring without fear of breaking everything, and of course, open source code that you can (and should) study.

In this article, we won't tell you how to install TypeScript. Instead, we'll head to GitHub and break down 7 best repositories that will not only show you elegant solutions but also help you write cleaner, safer, and more scalable code. Each project is a tutorial written in real code.

What are we looking for in repositories?

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• Architectural patterns — how to build a project so you don't want to delete it after a month.
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• Examples of strict typing — where TS shines 100%.
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• Real-world utility — libraries you can apply right now.
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Let's go!

1. NestJS — A Framework for Serious Applications

Repository: github.com/nestjs/nest

NestJS is arguably the most elegant TypeScript framework. It borrows ideas from Angular (modules, decorators, DI) and turns server-side code into a work of art.

Why study it:

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• Clear module separation.
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• Built-in support for GraphQL, WebSockets, RabbitMQ.
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• Documentation — a role model.
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Code example from the repository (controller and service):

// cats.controller.ts\nimport { Controller, Get, Post, Body } from '@nestjs/common';\nimport { CatsService } from './cats.service';\nimport { CreateCatDto } from './dto/create-cat.dto';\nimport { Cat } from './interfaces/cat.interface';\n\n@Controller('cats')\nexport class CatsController {\n  constructor(private catsService: CatsService) {}\n\n  @Post()\n  async create(@Body() createCatDto: CreateCatDto) {\n    this.catsService.create(createCatDto);\n  }\n\n  @Get()\n  async findAll(): Promise<Cat[]> {\n    return this.catsService.findAll();\n  }\n}\n

Notice the @Controller, @Get decorators and the strict Cat interface. This is not just code — it's a template used by hundreds of thousands of projects.

2. Prisma — An ORM That Doesn't Annoy You

Repository: github.com/prisma/prisma

Prisma is a modern ORM (Object-Relational Mapping) for TypeScript and Node.js. It automatically generates types based on your database schema. This means errors like "field does not exist" are caught at compile time, not at runtime.

What you'll take away: the "Schema-first" approach and automatic type generation.

Example from the documentation:

// schema.prisma\nmodel User {\n  id    Int     @id @default(autoincrement())\n  email String  @unique\n  name  String?\n  posts Post[]\n}\n\nmodel Post {\n  id        Int     @id @default(autoincrement())\n  title     String\n  content   String?\n  author    User    @relation(fields: [authorId], references: [id])\n  authorId  Int\n}\n\n// usage.ts\nimport { PrismaClient } from '@prisma/client';\n\nconst prisma = new PrismaClient();\n\nasync function main() {\n  const user = await prisma.user.create({\n    data: {\n      email: 'alice@prisma.io',\n      name: 'Alice',\n      posts: {\n        create: { title: 'Hello World' },\n      },\n    },\n  });\n  console.log(user);\n}\n

Prisma is a perfect example of how TypeScript can make working with data safe and fast.

3. RxJS — Rea