Update documentation/docs/30-advanced/70-packaging.md

Author: dummdidumm

documentation/docs/30-advanced/70-packaging.md

@@ -220,7 +220,20 @@ You should think carefully about whether or not the changes you make to your pac
 
 ## Source maps
 
-You can create so-called declaration maps (`d.ts.map` files) by setting `"declarationMap": true` in your `tsconfig.json`. This will allow editors such as VS Code to go to the original `.ts` or `.svelte` file when using features like _Go to Definition_. This means you also need to publish your source files alongside your dist folder in a way that the relative path inside the declaration files leads to a file on disk.
+You can create so-called declaration maps (`d.ts.map` files) by setting `"declarationMap": true` in your `tsconfig.json`. This will allow editors such as VS Code to go to the original `.ts` or `.svelte` file when using features like _Go to Definition_. This means you also need to publish your source files alongside your dist folder in a way that the relative path inside the declaration files leads to a file on disk. Assuming that you have all your library code inside `src/lib` as suggested by Svelte's CLI, this is as simple as adding `src/lib` to `files` in your `package.json`:
+
+```json
+{
+	"files": [
+		"dist",
+		"!dist/**/*.test.*",
+		"!dist/**/*.spec.*",
+		+++"src/lib",
+		"!src/lib/**/*.test.*",
+		"!src/lib/**/*.spec.*"+++
+	]
+}
+```
 
 ## Options