Ensuring type safety while working with third-party libraries that don't have TypeScript support can be challenging, but there are several strategies you can use to mitigate potential issues and improve the overall type safety in your TypeScript codebase: 1. Use Declaration Files (Type Definitions): TypeScript provides declaration files (with a .d.ts extension) that describe the shape of JavaScript libraries and APIs. Many popular JavaScript libraries have community-maintained or official declaration files available. By installing these declaration files using a package manager like npm or yarn, you can get type information for the third-party library. For example, if you're using a library called "example-library," you would install its types with `npm install @types/example-library`. 2. Create Custom Declaration Files: If a third-party library doesn't have official or up-to-date type definitions, you can create custom declaration files to describe the types for that library yourself. This can be time-consuming and may require some reverse-engineering, but it's a powerful way to add type safety to your interactions with the library. 3. Use "any" Type with Caution: Sometimes, when working with third-party libraries that lack type information, developers resort to using the "any" type to suppress type checking. While this approach allows you to bypass type errors, it undermines the benefits of using TypeScript. Instead, consider limiting the use of "any" and use type assertions only when absolutely necessary. 4. Encapsulate Unsafe Code: If you must interact with parts of a third-party library that lack type information or are inherently unsafe, consider encapsulating that code into a separate module or function. This way, you can contain the usage of "any" or unsafe types within a small part of your codebase and keep the rest of your application type-safe. 5. Enable "noImplicitAny" Flag: TypeScript has a compiler flag called "noImplicitAny." When enabled, it raises an error whenever TypeScript cannot infer a type and falls back to "any." Using this flag can help you catch instances where type information is missing or ambiguous. 6. Contribute to DefinitelyTyped: If you have experience with a third-party library and TypeScript, you can contribute by creating or improving declaration files on DefinitelyTyped. This helps the TypeScript community and improves type safety for everyone using that library. Conclusion : Remember that TypeScript can only provide type safety when it has enough type information to do so. While these strategies can help, there may still be limitations when working with poorly documented or dynamically typed libraries. It's essential to strike a balance between type safety and sensible use of third-party code in your projects.