Clarify Documentation on Emitting Declarations (.d.ts) Files

[phil-lgr]

Expected Behaviour

Have an option to output declarations files in webpack output folder

Actual Behaviour

ts-loader does not support it?

The official documentation points to a 7 years old plugin (https://github.com/TypeStrong/ts-loader#declarations-dts)

Steps to Reproduce the Problem

Declarations (.d.ts)
To output a built .d.ts file, you can set "declaration": true in your tsconfig, and use the DeclarationBundlerPlugin in your webpack config.

Did I miss something? I'd be happy to PR an update to the docs if it's out of date.

Thank you

[johnnyreilly]

Does the suggested approach in the documentation work?

[phil-lgr]

When I was looking on how to produce .d.ts files, I was very confused by this paragraph.

IMO, this section should answer the following questions:

• How can I configure ts-loader to output .d.ts files?
• How do I emit .d.ts. files when using ts-loader with transpileOnly = true and fork-ts-checker-webpack-plugin? (very common scenario?)
• How can I output a single bundled declaration file?

Here is a rough draft:

---

Declarations (.d.ts)

To output declaration files (.d.ts), you can set "declaration": true in your tsconfig and set "transpileOnly" to false.

If you use ts-loader with "transpileOnly": true along with fork-ts-checker-webpack-plugin, refer to the plugin's modes to output .d.ts files: https://github.com/TypeStrong/fork-ts-checker-webpack-plugin#typescript-options

To output a built .d.ts file, you can use the DeclarationBundlerPlugin in your webpack config.

---

Does that make sense to you? I've used ts-loader for years, and I am not even sure if it can output .d.ts files on its own, I always use it with fork-ts-checker-webpack-plugin, so please correct me.

[johnnyreilly]

Thanks for the draft, I didn't quite follow the meaning of this sentence:

refer to the plugin's modes to output .d.ts files

Otherwise looks great!

I've used ts-loader for years, and I am not even sure if it can output .d.ts files on its own

I have written and used ts-loader for years and I can't even remember 😅

[phil-lgr]

Ok what about:

---

Declarations (.d.ts)

To output declaration files (.d.ts), you can set "declaration": true in your tsconfig and set "transpileOnly" to false.

If you use ts-loader with "transpileOnly": true along with fork-ts-checker-webpack-plugin, you will need to configure fork-ts-checker-webpack-plugin to output definition files, you can learn more on the plugin's documentation page: https://github.com/TypeStrong/fork-ts-checker-webpack-plugin#typescript-options

To output a built .d.ts file, you can use the DeclarationBundlerPlugin in your webpack config.

---

[johnnyreilly]

Looks great!

[phil-lgr]

You want a PR for that, or you can just copy and paste and update the README? lmk

[johnnyreilly]

PR please!