Understanding the Execution Models of async JavaScript and React

Kai Wohlfahrt
Nov 7, 2019 · 12 min read

You may have heard somebody mention React Fibers recently, and even more recently that Suspense lets you use async functions with React. Read on for a dive into what an async function is, and what they have to do with Fibers!


In 2017, JavaScript gained the async/await syntax, on top of 2015’s generator functions (function*/yield). This section explores what these language features do, and how they relate to React’s rendering model.

Function Calls