Lesson 1.3
Finding wasted renders
Most React slowness is a subtree re-rendering for no reason. Track it back to the prop or context value that changes identity on every render.
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Overview
Most React slowness is a subtree re-rendering for no reason. Track it back to the prop or context value that changes identity on every render.
What this lesson covers
- Trace a re-render back to the prop that changed
- Spot object and function props recreated each render
- Recognise context as a re-render broadcast
This lesson sits in Measuring Performance, part of React Performance Engineering. It assumes what came before it and leads directly into the next lesson in the module.
In this lesson you will:
- Trace a re-render back to the prop that changed
- Spot object and function props recreated each render
- Recognise context as a re-render broadcast