I just started studying front-end development and I'm struggling with a node.js error. Typing 'npm start' in my VSCode terminal used to work fine for simple tutorial projects with just an index.html, script.js, and style.css file. (without a package.json file)

However after trying out React for the first time, 'npm start' now doesn't work anymore in my other non-React projects. At first it was giving me an error that it was missing the package.json (which it didn't need before?) but after trying to fix it with help of googling I now got to a point where it's giving me the error: Missing script: "start".

How can I run node without creating package.json files for every small tutorial project I've made previously, or without turning them into React apps? Also why is this happening? Did installing React-native create dependencies of some sort?

Thanks in advance!

I already tried reinstalling node.js and tried different versions. Also tried deleting package-lock.json. It still works for React apps, just not with simpler native javascript apps.

CodePudding user response：

A package.json file is required if you want to install any packages or run scripts in your terminal. In your package.json file, make sure you have added scripts property. This is an example of how you can use it:

{
  ...
  "scripts": {
    "start": "react-scripts start"
  }
}

Remove ... from the snippet if you're copying, this has been added to indicate that there are one or more fields in this JSON file.

After you have added this to your package file, you will be able to run the start script by typing npm run start in the terminal or if you use Yarn: yarn start.

Edit: You said that running npm start in your React project is running fine, but on your simpler projects with only a simple HTML, CSS and JS file is not working when using the script.

You are probably confusing npm start with node file.js. Where node file.js doesn't require a package to be in your project to run a JavaScript file, using npm start requires you to have a JSON file present in your project folder with the JSON code as in my answer.

So long story short: Using npm start requires package.json with the script property available. While node file.js doesn't require you to have this file in your project.

CodePudding user response：

if you are using react-native you can do the following

• First you have to build your project with the command

  npx react-native run-android , npx react-native run-ios

• Once your project has build successfully and app is installed on your device then you your development server is started already. for some reason if your server is closed then you can run it with the command given below.

• adb reverse tcp:8081 tcp:8081 this will send a signal to your device and after this run npx react-native start