We recently ported our 30,000 lines of JavaScript code from Flow to TypeScript, as we sought to leverage statically and strongly typed JavaScript for better type safety, reduced runtime errors, and improved developer productivity. We found that using TypeScript provided us with a more robust set of features compared to Flow, such as better support for third-party dependencies, enhanced editor/IDE integrations, and improved performance. However, we also encountered some challenges during the porting process, including fixing syntax errors, type inference issues, and adjusting our code to accommodate TypeScript's stricter standards. Ultimately, after one engineer week of work, we successfully fixed all remaining type errors and have been using TypeScript since then.