TypeScript Best Practices

What this best practices guide is

A practical guide to writing TypeScript that catches real bugs without fighting you. It covers compiler settings for TypeScript 6 and 7, modeling data with types, avoiding unsafe escape hatches, validating data at runtime boundaries, generics, typed linting and organizing larger codebases, with short examples you can copy.

It has 7 chapters and 33 practices, each with why it matters, what to do and what to avoid. For JavaScript and TypeScript developers.

Chapter by chapter

1. Compiler settings and TypeScript 7 (6 practices)

The tsconfig decides how much TypeScript checks for you. This chapter covers the strict flags, module settings for your runtime and the move to the native TypeScript 7 compiler.

2. Modeling data with types (6 practices)

Good types describe the states your data can really be in, and nothing else. This chapter covers unions, literal types, readonly data and where to write annotations.

3. Avoiding unsafe escape hatches (5 practices)

any, type assertions, non-null assertions and ignore comments switch off the checks you turned on. This chapter shows the safer tools for each case.

4. Validating data at runtime boundaries (4 practices)

Types are erased before your code runs. This chapter covers validating data where it enters the program, typing configuration and handling errors safely.

5. Generics and utility types (4 practices)

Generics let one function or type work with many types while keeping them related. This chapter follows the handbook guidelines for simple, useful generics and built-in utility types.

6. Typed linting and async code (4 practices)

Some bugs type check fine but are still bugs, especially around promises. This chapter covers type-aware linting and safe async patterns.

7. Organizing larger codebases and libraries (4 practices)

As a codebase grows, build speed, boundaries and published types matter more. This chapter covers project references, library publishing and keeping dependencies healthy.

How it works on Sefism

The guide reads like a short course: a syllabus, then one chapter per page in a focused reader, with a quiz at the end of each chapter for members. The opening chapters are open to everyone. Adding it to your account uses credits, opens every chapter and keeps your progress.

Every claim is checked against the sources listed on the page (8 cited).