https://wiki.quizz.vn/ 2026-04-15T18:03:05+00:00 https://wiki.quizz.vn/ https://wiki.quizz.vn/lib/exe/fetch.php?media=wiki:dokuwiki.svg text/html 2026-01-05T23:14:35+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.quizz.vn/doku.php?id=go:errors:custom_errors&rev=1767654875&do=diff Custom errors What is it? A custom error is your own error type (usually a struct) that implements `Error() string`. It may include extra fields (code, operation, resource ID, etc.). What is it used for? * Return structured error details. * Enable typed checks with `errors.As`. text/html 2026-01-05T23:12:30+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.quizz.vn/doku.php?id=go:errors:error_interface&rev=1767654750&do=diff error interface What is it? `error` is a built-in interface type in Go: type error interface { Error() string } Any type that implements `Error() string` can be used as an error. What is it used for? * Standardize how functions return failure information. text/html 2026-01-05T23:22:32+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.quizz.vn/doku.php?id=go:errors:error_wrapping&rev=1767655352&do=diff Error wrapping (%w) What is it? Error wrapping means adding context to an error while keeping the original error inside it. In Go, `fmt.Errorf` supports wrapping using `%w`: fmt.Errorf("doing X: %w", err) What is it used for? * Add helpful context at each layer (repo → usecase → handler). text/html 2026-01-05T23:16:00+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.quizz.vn/doku.php?id=go:errors:sentinel_errors&rev=1767654960&do=diff Sentinel errors What is it? A sentinel error is a package-level variable used as a fixed, recognizable error value. Example: var ErrNotFound = errors.New("not found") What is it used for? * Let callers check for a specific error using equality (`err == ErrNotFound`) text/html 2026-01-05T23:11:28+00:00 Anonymous (anonymous@undisclosed.example.com) https://wiki.quizz.vn/doku.php?id=go:errors:start&rev=1767654688&do=diff Error Handling What is it? In Go, errors are values returned from functions. The common pattern is: return `(result, error)` and check `if err != nil`. What is it used for? * Report failures without exceptions. * Keep control flow explicit. *