Скачать или смотреть Resolving TypeScript Type Issues in AWS-CDK App Definitions

Learn how to fix TypeScript type issues in your AWS-CDK project by managing type imports and paths effectively.
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Resolving TypeScript Type Issues in AWS-CDK App Definitions

If you've been using AWS-CDK with TypeScript, you might have encountered an issue where your custom types, defined in a local typings folder, are not being recognized within your CDK app definitions. This is particularly frustrating, especially when they seem to work perfectly in other sections of your code, such as Lambda functions. In this guide, we'll explore the problem and provide a solution to ensure that your custom types are properly recognized in your CDK application.

Understanding the Problem

When you define global types in a TypeScript project, you would expect them to be available throughout your entire codebase, including in your CDK app files. However, in certain scenarios, especially when it comes to CDK, TypeScript might not recognize these types due to how they are imported or the configurations set in your tsconfig.json. The result is an error stating that TypeScript cannot find the types.

Example Scenario

Imagine you have a project folder structure like the following:

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In this setup, you might have defined a custom type in common.ts like so:

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Yet, when trying to use EventType in your CDK files, you encounter an error that indicates that the type cannot be found.

Solution: Utilize Type Imports Effectively

To resolve this issue, you can create a dedicated index file in your typings directory to import all necessary type files without doing explicit exports. This method ensures that the TypeScript compiler understands and includes these types when building your project.

Step-by-Step Solution

Create an Index File for Typings: Inside your typings folder, create a new file named index.ts. In this file, import all of your type files:

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If you have more type files, simply add more import statements for each.

Import the Typings in Your CDK File: In your main CDK application file (e.g., cdk-app.ts), you can now import the typings directory to include your types:

[[See Video to Reveal this Text or Code Snippet]]

Key Concepts

No Export Needed: The assumption that you could not import something that was not exported is a common misconception. By merely importing, you are allowing TypeScript to recognize the type definitions without needing exports.

Avoiding typeRoots Overheads: Relying heavily on typeRoots can create confusion and may not be the best approach, especially in large projects. Utilizing an index file keeps your types organized and accessible.

Conclusion

By following these steps, you can effectively resolve the issue of TypeScript not recognizing your custom types in AWS-CDK app definitions. Remember, the key lies in properly structuring your imports. With a clear organization of your type definitions, you can ensure a smoother development experience and leverage the full power of TypeScript in your AWS projects.

If you happen to have any questions or need further assistance while navigating TypeScript issues in your AWS-CDK projects, feel free to reach out!