How to assess performance of unknown React application

Question

Lets say I start working in a new company on an existing large React application. How would I assess its performance as a whole? Efficiency of rendering mostly. Are there any tools for that?

Answer 1

1. Get help from React.Profiler component.

React 16.5 adds support for a new DevTools profiler plugin. This plugin uses React's experimental Profiler API to collect timing information about each component that's rendered in order to identify performance bottlenecks in React applications. It will be fully compatible with our upcoming time slicing and suspense features.

2. Use the react-addons-perf package that tells you exactly where you need to put these methods.

As of React 16, react-addons-perf is not supported. Please use your browser's profiling tools to get insight into which components re-render