Inspect and Decode Your JWT Tokens JWT Inspector tool for network operations.

The tool works by first taking the input JWT token and splitting it into three parts using the dot character as a separator. It then uses the `atob` function to decode each part from base64url encoding to a JSON string, which is then parsed into a JavaScript object using `JSON.parse`. The `base64UrlDecode` function is used to handle the specifics of base64url decoding, including replacing hyphens and underscores with plus signs and slashes, and padding the string with equals signs as needed. This process allows it to extract the header, payload, and signature from the token.

The tool uses React hooks, specifically `useState` and `useCallback`, to manage its state and handle user interactions such as decoding the token and copying the header or payload to the clipboard. The `copyToClipboard` function is used to handle the actual copying of text to the clipboard, using browser APIs to interact with the clipboard. When decoding the token, it checks if the payload contains an expiration time and issues a warning if the token has expired. It also extracts other relevant information from the payload, such as the subject and issuance time, and displays this information in a user-friendly format.

The tool is built using modern JavaScript features, including ES6+ syntax and React hooks, and follows best practices for security and responsiveness. It uses a mobile-first approach to ensure that it works well on smaller screens, and it handles edge cases such as invalid input tokens by displaying an error message. The `decodeURIComponent` function is used to handle any URL-encoded characters in the token, ensuring that the decoded data is accurate and reliable. By using these technologies and techniques, the tool provides a fast and secure way to decode and analyze JWT tokens in the browser.