Lesson 1.2
Core Web Vitals in a React app
Lab numbers on your laptop are not what users experience. Vitals give you a field measure of loading, responsiveness, and visual stability.
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Overview
Lab numbers on your laptop are not what users experience. Vitals give you a field measure of loading, responsiveness, and visual stability.
What this lesson covers
- Interpret LCP, INP, and CLS in practical terms
- Separate lab data from field data
- Attribute a poor score to a specific element or interaction
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:
- Interpret LCP, INP, and CLS in practical terms
- Separate lab data from field data
- Attribute a poor score to a specific element or interaction
Pro Tip
A good score on your machine means very little. Look at the field data from real devices.