Flow - Am I Your Type?

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.

Intro
Outline
Static vs. Dynamic
Why Use Types?
Why Avoid Types?
Flow Overview
TypeScript Overview
Comparing Flow & TypeScript
Installing Flow
Running Flow
Type Suggestions
Executing Code With Types ...
Flow Analysis Example
Uninitialized References
Flow Types
Maybe Type
Basic Types Example
Builtin Types
Functions
Arrays
Objects
Classes
Unions For Enums
Sharing Type Aliases Example
Escape Hatch
Flow Server ...
Flow Project Checklist
Dev Dependencies
Recommended npm Scripts
Babel Setup
flowconfig File
flow-typed
Editor/IDE Setup...
Sample Project
Project Dependencies
The Code ...
Summary
Bonus Slides
Nominal vs. Structural Typing
Variance in Flow & TypeScript
Soundness vs. Correctness