Fix console write with missing level field

console.go

@@ -328,7 +328,11 @@ func consoleDefaultFormatLevel(noColor bool) Formatter {
 				l = colorize("???", colorBold, noColor)
 			}
 		} else {
-			l = strings.ToUpper(fmt.Sprintf("%s", i))[0:3]
+			if i == nil {
+				l = colorize("???", colorBold, noColor)
+			} else {
+				l = strings.ToUpper(fmt.Sprintf("%s", i))[0:3]
+			}
 		}
 		return l
 	}

console_test.go

@@ -159,6 +159,22 @@ func TestConsoleWriter(t *testing.T) {
 		}
 	})
 
+	t.Run("No level field", func(t *testing.T) {
+		buf := &bytes.Buffer{}
+		w := zerolog.ConsoleWriter{Out: buf, NoColor: true}
+
+		_, err := w.Write([]byte(`{"message": "Foobar", "foo": "bar"}`))
+		if err != nil {
+			t.Errorf("Unexpected error when writing output: %s", err)
+		}
+
+		expectedOutput := "<nil> ??? Foobar foo=bar\n"
+		actualOutput := buf.String()
+		if actualOutput != expectedOutput {
+			t.Errorf("Unexpected output %q, want: %q", actualOutput, expectedOutput)
+		}
+	})
+
 	t.Run("Write colorized fields", func(t *testing.T) {
 		buf := &bytes.Buffer{}
 		w := zerolog.ConsoleWriter{Out: buf, NoColor: false}