In which tasks is Node.js most effective, and in which does it perform the worst?

Node.js is most effective in tasks that require high performance when handling a large number of concurrent connections with low CPU load. This includes, for example:

• Web servers and APIs that process many input-output (I/O) requests, such as database queries, filesystem access, or external services.
• Real-time applications like chats, games, streaming, where asynchronous event handling is crucial.
• Proxy servers that redirect requests and work with networks.

Node.js performs poorly in tasks with intensive CPU computations, such as:

• Complex mathematical calculations, processing large data arrays in memory.
• Tasks requiring multithreaded processing, where Node.js is limited by its single-threaded event loop.

In such cases, it is better to use specialized languages or run heavy computations in separate processes or services.