React: Each Class is executing two times in react version 16.13.1

[radhey7705]

React version: 16.13.1
React Script Version: 3.4.1

Steps To Reproduce

1. Just create a new project using command npx create-react-app
2. Convert functional component to Class component in App.js
3. Add a console log before "return" statement.
4. then run command "npm start"
5. In the console in browser, you will see console log was printed two times.

Link to code example: https://github.com/radhey7705/React-Project.git

The current behavior

after run npm start, Class component is working two times

The expected behavior

after run npm start, Class component should only work single time.

[Reflex-Gravity]

In Strict Mode, react intentionally double-invokes constructor, render, and shouldComponentUpdate.
It helps to detect unexpected side effects.

More details in the below link:
https://reactjs.org/docs/strict-mode.html#detecting-unexpected-side-effects

[bvaughn]

This is intentional, as mentioned above 😄 so I am going to close this issue.

Thanks for leaving the link, @Reflex-Gravity