Omit Empty / Zero

OmitEmpty

OmitEmpty omits fields that are semantically “nothing”: nil, empty strings "", and nil or empty slices and maps.

clog.SetOmitEmpty(true)
clog.Info().
  Str("name", "alice").
  Str("nickname", "").   // omitted
  Any("role", nil).      // omitted
  Int("age", 0).         // kept (zero but not empty)
  Bool("admin", false).  // kept (zero but not empty)
  Msg("User")
// INF ℹ️ User name=alice age=0 admin=false

OmitZero

OmitZero is a superset of OmitEmpty - it additionally omits 0, false, 0.0, zero durations, and any other typed zero value.

clog.SetOmitZero(true)
clog.Info().
  Str("name", "alice").
  Str("nickname", "").   // omitted
  Any("role", nil).      // omitted
  Int("age", 0).         // omitted
  Bool("admin", false).  // omitted
  Msg("User")
// INF ℹ️ User name=alice

Both settings are inherited by sub-loggers created with With(). When both are enabled, OmitZero takes precedence.

Both settings also apply to animated task rows (Task, Group tasks, progress bars): an empty field stays hidden while the row is live and appears in place - preserving its declared position - once it is given a value via a live Update or the task result. This makes it possible to reserve a slot for a late-arriving field (e.g. a URL) ahead of elapsed without rendering an empty url= in the meantime.