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TypeScript Academy · Lesson

Declarations, source maps, types exports

Generate declaration files, enable source maps for debugging, and learn strategies to export types.

Declarations, source maps, types exports is a free TypeScript Academy lesson on CoddyKit — lesson 3 of 3. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the TypeScript Academy learning path, one of 3 lessons in the course, and your progress syncs across the web and the CoddyKit app.

Intro

Goal: Learn how to produce declaration files, enable source maps, and export types clearly.

Declarations

Enable declaration: true to generate .d.ts files along with JS output.

// tsconfig.json
{
  "compilerOptions": {
    "declaration": true,
    "outDir": "dist"
  }
}

emitDeclarationOnly

Use emitDeclarationOnly to produce only type declarations (no JS) for libraries.

// tsconfig.json
{
  "compilerOptions": {
    "emitDeclarationOnly": true,
    "outDir": "types"
  }
}

Source maps

Source maps let you debug TS in browsers or Node, mapping JS back to TS code.

// tsconfig.json
{
  "compilerOptions": {
    "sourceMap": true
  }
}

package.json types

Use the types or typings field in package.json to point to entry declarations.

// package.json
{
  "types": "dist/index.d.ts"
}

Re-export

Re-export types for public API clarity. Combine with declaration for consumers.

// src/index.ts
export type { User, Config } from "./models";
export { createClient } from "./client";

Question

Quick check: Which compiler option enables .d.ts generation?

Recap

Recap: declaration creates .d.ts, emitDeclarationOnly outputs types only, sourceMap aids debugging, and re-exports shape your public API.

Frequently asked questions

Is the “Declarations, source maps, types exports” lesson free?

Yes — the full text of “Declarations, source maps, types exports” is free to read here on the web, and the TypeScript Academy course includes 3 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the TypeScript Academy course, upgrade to CoddyKit PRO.

What will I learn in “Declarations, source maps, types exports”?

Generate declaration files, enable source maps for debugging, and learn strategies to export types. You practise TypeScript Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start TypeScript Academy?

No prior experience is required. TypeScript Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 3 of 3, so you can start here or from the beginning and move at your own pace.

How long does the “Declarations, source maps, types exports” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this TypeScript Academy lesson?

Yes. Every TypeScript Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

All lessons in this course

  1. tsc emit vs noEmit + bundlers
  2. Vite / esbuild / SWC / Rollup basics
  3. Declarations, source maps, types exports
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