title: How to fix `npm start` opening the wrong React app
body: <p>I have been working on a React app, let's call it app A. Then I cloned app B on a different directory and worked a little on it. The next day I went back to app A and tried <code>yarn start</code>. It opened app B on <code>3000</code>. I checked the directory, the <code>package.json</code> file, tried <code>npm start</code>. The same result. So I deleted app B from my device. To my surprise the same result. I found a workaround: I open a new terminal and run <code>yarn start</code> while app B is open, says the port is being used, do you want to open in a different port? <strong>Yes</strong>. Opens app A on <code>3001</code>. Its been a couple of days and still the same thing. The only thing I haven't tried is deleting <code>node_modules</code> and running <code>yarn</code> or <code>npm i</code>. Does anyone know why this happens and how it can be fixed?</p>