Explore the fundamentals of Flow, an open-source static type checker for JavaScript, in this comprehensive 58-minute conference talk. Learn how to gradually add types to your JavaScript code, catch errors through type inference and flow analysis, and understand the differences between Flow and TypeScript. Dive into various Flow types, including primitives, functions, arrays, objects, and generic classes. Discover how to set up Flow in your development environment, integrate it with Babel and ESLint, and leverage its React and JSX support. Gain insights into the benefits and potential drawbacks of using types in JavaScript, and explore advanced topics such as type aliases, generics, interfaces, and disjoint unions. By the end of this talk, acquire the knowledge needed to effectively implement Flow in your projects and enhance your JavaScript development workflow.