How can you re-throw or propagate an error in Node.js?

Re-throwing or propagating an error means catching an error, potentially performing some initial handling (like logging or adding context), and then throwing it again so it can be caught by an outer `try...catch` block or a global error handler. This is useful when a function detects an error but isn't solely responsible for its ultimate recovery, allowing a higher-level component to decide how to handle it. ```javascript function processFileContent(content) { try { if (!content || content.length === 0) { throw new Error("File content cannot be empty."); } // Assume further processing here console.log("Content processed successfully."); } catch (error) { console.warn("Warning: Issue in content processing, re-throwing for upstream handling."); // Log details here if needed, but don't fully handle the error throw error; // Re-throw the original error } } try { // This call will cause an error that is re-thrown processFileContent(""); } catch (mainError) { console.error("Caught re-thrown error at main application level:", mainError.message); console.error(mainError.stack); } ``` This pattern allows for layered error handling, where specific modules can add context or perform localized cleanup before passing the error up the call stack.