How to Export TypeScript Types in Svelte Files

Description

A comprehensive guide on how to properly export TypeScript types from Svelte files, addressing common issues and providing solutions. --- This video is based on the question https://stackoverflow.com/q/64064506/ asked by the user 'Alireza' ( https://stackoverflow.com/u/2823226/ ) and on the answer https://stackoverflow.com/a/64066160/ provided by the user 'dummdidumm' ( https://stackoverflow.com/u/10196188/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions. Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: export typescript type in svelte file Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/licensing The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license. If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com. --- How to Export TypeScript Types in Svelte Files When working with Svelte and TypeScript, it's common to encounter challenges while trying to export types defined in your Svelte components. If you've run into errors like "Modifiers cannot appear here" while trying to export your types, you're not alone. This post will guide you through the process of exporting TypeScript types from a Svelte file correctly, ensuring you can seamlessly integrate types into your project. Understanding the Problem You might have defined a TypeScript type in a Svelte file like this: [[See Video to Reveal this Text or Code Snippet]] However, when you attempt to export the type directly from your Svelte file, you end up facing the linter error stating "Modifiers cannot appear here." This error can be frustrating, especially if your current setup uses the Sapper template and TypeScript functionality seems broken in your development environment. The Solution Fortunately, there's a straightforward way to export types from Svelte files by using module-scripts. Below we'll outline the steps to resolve the issue effectively. Step-by-Step Guide 1. Use a Module-Script To export types from a Svelte file, you need to utilize the <script context="module"> tag. Here’s how you can structure your Svelte file: [[See Video to Reveal this Text or Code Snippet]] Explanation: context="module": This tells Svelte that the script will run in the module context, allowing you to define exports that can be imported in other files. lang="ts": Ensure you specify the language as TypeScript, so the file is processed appropriately. 2. Importing the Types in Another File Once you have defined and exported your types correctly, you can import them into another Svelte file like this: [[See Video to Reveal this Text or Code Snippet]] Additional Notes TypeScript in Svelte: Whenever you want to import something that is not a component itself from another Svelte file, ensure you use the module context for your exports. Using a Separate TypeScript File: While it is possible to create a separate .ts file for your types, following the above steps will allow you to keep your types within Svelte without the need for additional files. Conclusion Exporting TypeScript types from Svelte files can initially seem daunting, especially when faced with linter issues. By utilizing module-scripts and following the structured steps outlined above, you can effectively manage TypeScript types in your Svelte applications. This not only keeps your projects organized but also leverages the full potential of TypeScript's type-checking capabilities. Happy coding!