Decode Percent-Encoded URLs to Readable Text Decode percent-encoded URL strings back to readable text.

The UrlDecoder component relies on React's useCallback hook to memoize the onProcess function, which takes an input string and attempts to decode it using the decodeURIComponent function from JavaScript's standard library. This function iterates over each character in the input string, converting percent-encoded sequences like %20 back into their corresponding byte values, and reassembling multi-byte UTF-8 sequences into Unicode characters. If the input contains invalid percent-encoding sequences, such as %ZZ or incomplete sequences, decodeURIComponent throws a URIError that is caught by the tool and reported to the user.

Under the hood, decodeURIComponent uses a combination of bitwise operations and lookup tables to efficiently convert percent-encoded sequences back into their original byte values. The function preserves plus signs (+) as-is, since they are used in application/x-www-form-urlencoded format to represent spaces, whereas standard percent-encoding uses %20 for this purpose. When the tool is rendered, it uses the TextToolLayout component from the @/components/shared module, passing in the onProcess function and other props like inputPlaceholder and outputLabel to customize its appearance and behavior.

The use of React's useCallback hook ensures that the onProcess function is only recreated when the component's dependencies change, which helps to prevent unnecessary re-renders and improve performance. Additionally, the try-catch block around decodeURIComponent provides a clear error handling mechanism, allowing the tool to provide informative error messages to users who input invalid URL-encoded strings. The decoded text is then displayed in a labeled output field, making it easy for users to compare the original input with its decoded counterpart.