(new): JSON HTML escaping control

- add Formatter.JSONEscapeHTML and SetJSONEscapeHTML to let JSON writers preserve HTML-sensitive characters when needed while keeping escaping enabled by default.
- switch JSON output to json.Encoder, preserve existing Print/Println newline semantics, and cover the new escaping behavior in tests.

RELEASE_NOTES.md

@@ -1,4 +1,27 @@
-# Unreleased (planned v2.2.0)
+# v2.3.0
+
+This release adds JSON HTML-escaping control while preserving the existing
+JSON writer defaults and newline semantics.
+
+### Added
+
+- Added `Formatter.SetJSONEscapeHTML(bool)` and `Formatter.JSONEscapeHTML` to control whether JSON writers escape HTML-sensitive characters such as `<`, `>`, and `&`.
+
+### Changed
+
+- JSON writers now use `json.Encoder` internally so formatter-level HTML escaping can be configured.
+
+### Fixed
+
+- Preserved `Print` and `Println` newline behavior for JSON output while switching to `json.Encoder`.
+
+### Compatibility
+
+- No breaking API changes.
+- HTML escaping remains enabled by default, matching the previous `encoding/json` behavior.
+- `Print` still emits JSON without an added newline, and `Println` emits exactly one trailing newline.
+
+# v2.2.0
 
 This release expands the public LogLevel API, adds optional threshold-based
 filtering alongside the legacy severity ordering, and improves documentation

examples/main.go

@@ -32,6 +32,7 @@ func main() {
 	jsonFormatter := sneklog.NewFormatter().
 		SetFormat("[%L] [%N] %m").
 		SetColorOutput(false).
+		SetJSONEscapeHTML(false).
 		SetTimeStampFormat(sneklog.Kitchen)
 
 	textStdout.SetFormatter(formatter)
@@ -62,6 +63,7 @@ func main() {
 		externalJSON,
 	)
 
+	logger.Infoln("Тест <>&")
 	logger.Infoln("service started")
 	logger.Warnln("cache miss")
 	logger.Errorln("request failed")

formatter.go

@@ -32,9 +32,10 @@ type Formatter struct {
 	Format           string
 	MessageSeparator string
 
-	// JSONTraceBackPath
-	// If true, in traceback will be path to file, otherwise only filename.
+	// JSONTraceBackPath enables full file paths in formatted traceback fields.
 	JSONTraceBackPath bool
+	// JSONEscapeHTML controls whether JSON output escapes HTML-sensitive characters.
+	JSONEscapeHTML     bool
 	TimeStampFormat    string
 	TraceBackFormat    string
 	TraceBackSeparator string
@@ -57,6 +58,7 @@ var DefaultTextFormatter = &Formatter{
 // DefaultJsonFormatter is the default formatter used by JSON writers.
 var DefaultJsonFormatter = &Formatter{
 	Format:           "%m",
+	JSONEscapeHTML:   true,
 	MessageSeparator: " ",
 	TimeStampFormat:  RFC3339,
 	ColorOutput:      false,
@@ -67,6 +69,7 @@ func NewFormatter() *Formatter {
 	return &Formatter{
 		Format:             DefaultTextFormatter.Format,
 		MessageSeparator:   DefaultTextFormatter.MessageSeparator,
+		JSONEscapeHTML:     true,
 		TimeStampFormat:    DefaultTextFormatter.TimeStampFormat,
 		TraceBackFormat:    DefaultTextFormatter.TraceBackFormat,
 		TraceBackSeparator: DefaultTextFormatter.TraceBackSeparator,
@@ -87,6 +90,18 @@ func (f *Formatter) SetMessageSeparator(separator string) *Formatter {
 	return f
 }
 
+// SetJSONTraceBackPath enables or disables full file paths in formatted traceback fields.
+func (f *Formatter) SetJSONTraceBackPath(set bool) *Formatter {
+	f.JSONTraceBackPath = set
+	return f
+}
+
+// SetJSONEscapeHTML enables or disables HTML escaping in JSON output.
+func (f *Formatter) SetJSONEscapeHTML(escape bool) *Formatter {
+	f.JSONEscapeHTML = escape
+	return f
+}
+
 // SetTimeStampFormat sets the strftime-like format used for timestamps.
 func (f *Formatter) SetTimeStampFormat(format string) *Formatter {
 	f.TimeStampFormat = format

logger_test.go

@@ -342,6 +342,42 @@ func TestJsonWriterPrintAllowsEmptyMessages(t *testing.T) {
 	}
 }
 
+func TestJsonWriterPrintDoesNotAppendNewline(t *testing.T) {
+	var buf bytes.Buffer
+	writer := CreateJsonWriter(&buf, false)
+
+	if err := writer.Print(INFO, "TEST", nil, "hello"); err != nil {
+		t.Fatalf("Print() error = %v", err)
+	}
+
+	if bytes.HasSuffix(buf.Bytes(), []byte("\n")) {
+		t.Fatalf("Print() should not append newline, got %q", buf.String())
+	}
+}
+
+func TestJsonWriterSetJSONEscapeHTML(t *testing.T) {
+	var escaped bytes.Buffer
+	escapedWriter := CreateJsonWriter(&escaped, false)
+
+	if err := escapedWriter.Print(INFO, "TEST", nil, "<>&"); err != nil {
+		t.Fatalf("Print() with default formatter error = %v", err)
+	}
+	if strings.Contains(escaped.String(), "<>&") {
+		t.Fatalf("default JSON output should escape HTML-sensitive characters, got %q", escaped.String())
+	}
+
+	var raw bytes.Buffer
+	rawWriter := CreateJsonWriter(&raw, false).
+		SetFormatter(NewFormatter().SetFormat("%m").SetJSONEscapeHTML(false))
+
+	if err := rawWriter.Print(INFO, "TEST", nil, "<>&"); err != nil {
+		t.Fatalf("Print() with SetJSONEscapeHTML(false) error = %v", err)
+	}
+	if !strings.Contains(raw.String(), "<>&") {
+		t.Fatalf("SetJSONEscapeHTML(false) should preserve HTML-sensitive characters, got %q", raw.String())
+	}
+}
+
 func TestJsonWriterPrintPreservesTrailingNewlineSemantic(t *testing.T) {
 	var buf bytes.Buffer
 	writer := CreateJsonWriter(&buf, false)
@@ -354,6 +390,9 @@ func TestJsonWriterPrintPreservesTrailingNewlineSemantic(t *testing.T) {
 	if !bytes.HasSuffix(data, []byte("\n")) {
 		t.Fatalf("JSON output should end with newline, got %q", data)
 	}
+	if bytes.HasSuffix(bytes.TrimSuffix(data, []byte("\n")), []byte("\n")) {
+		t.Fatalf("JSON output should end with exactly one newline, got %q", data)
+	}
 
 	var message LoggerJsonMessage
 	if err := json.Unmarshal(bytes.TrimSuffix(data, []byte("\n")), &message); err != nil {

writers.go

@@ -1,6 +1,7 @@
 package sneklog
 
 import (
+	"bytes"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -145,22 +146,28 @@ func (w *LoggerJsonWriter) Print(level LogLevel, prefix string, traceback []*Met
 		Message:   s,
 		Traceback: traceback,
 	}
-	var data []byte
-	var err error
+
+	buf := bytes.NewBuffer(nil)
+	enc := json.NewEncoder(buf)
+	enc.SetEscapeHTML(f.JSONEscapeHTML)
 	if w.pretty {
-		data, err = json.MarshalIndent(m, "", "  ")
-	} else {
-		data, err = json.Marshal(m)
+		enc.SetIndent("", "  ")
 	}
+
+	err := enc.Encode(m)
 	if err != nil {
 		return err
 	}
-	if newline {
-		data = append(data, '\n')
+	data := buf.Bytes()
+	if !newline {
+		data = bytes.TrimSuffix(data, []byte("\n"))
 	}
-	_, err = w.Write(data)
+	_, err = w.writer.Write(data)
+	if err != nil {
 		return err
 	}
+	return nil
+}
 
 // Close closes the owned writer, if any.
 func (w *LoggerJsonWriter) Close() error {