Cannot use JSX unless the '--jsx' flag is provided

The error message "Cannot use JSX unless the '--jsx' flag is provided" typically occurs when you're working with TypeScript and trying to use JSX syntax without specifying the JSX option in your TypeScript configuration.

To resolve this issue, you need to ensure that your TypeScript configuration includes the appropriate JSX option. Here's how you can do that:

tsconfig.json:
Open your tsconfig.json file, which is typically located at the root of your TypeScript project. If you don't have a tsconfig.json file, you can create one.

Add JSX Option:
Make sure your tsconfig.json includes the "jsx" option. It should look something like this:

{
  "compilerOptions": {
    "target": "es6", // or your target version
    "module": "commonjs", // or your module system
    "jsx": "react", // or "preserve" if you're using another JSX-compatible library
    // other compiler options...
  },
  // other configuration options...
}

The important line here is "jsx": "react". This specifies that you are using JSX syntax with React. If you are using a different JSX-compatible library, you might need to adjust this value accordingly.

Save the File:
Save the tsconfig.json file after making these changes.

Restart the TypeScript Server (if applicable):
If you have a TypeScript server running (for example, if you're using Visual Studio Code with the TypeScript extension), you might need to restart it for the changes to take effect.

After making these changes, the error should be resolved, and you should be able to use JSX syntax in your TypeScript files without encountering the "--jsx" flag error.