react component not found error when I Cut and paste again codes of page

Hello, I used to cut the page codes in the react JS component file on my laptop to see if the page was rendered and to see if I opened the corresponding page code, and after the page turned white, I pasted the codes to the page. I was turning Now, on the new laptop where I had installed WebStorm, and after I pasted the cut codes again, I got the error that the corresponding component did not exist, and I had to stop the project from the terminal and start it again.
Do you have a solution for this? thank you