Updating JSON encoding

fmt.go

@@ -301,6 +301,11 @@ func FormatBytes(src []byte, invalid []byte, invalidWidth int, isJSON, isRaw boo
 				res.Buf = append(res.Buf, invalid...)
 				res.Width += invalidWidth
 				res.Quoted = true
+			} else if isJSON {
+				res.Buf = append(res.Buf, '\\', 'u')
+				for s := 12; s >= 0; s -= 4 {
+					res.Buf = append(res.Buf, lowerhex[r>>uint(s)&0xf])
+				}
 			} else {
 				res.Buf = append(res.Buf, '\\', 'x', lowerhex[src[0]>>4], lowerhex[src[0]&0xf])
 				res.Width += 4
@@ -311,22 +316,38 @@ func FormatBytes(src []byte, invalid []byte, invalidWidth int, isJSON, isRaw boo
 		// handle json encoding
 		if isJSON {
 			switch r {
-			case '\t':
-				res.Buf = append(res.Buf, '\\', 't')
+			case '\a':
+				res.Buf = append(res.Buf, '\\', 'u', '0', '0', '0', '7')
+				res.Width += 6
+				continue
+			case '\b':
+				res.Buf = append(res.Buf, '\\', 'b')
+				res.Width += 2
+				continue
+			case '\f':
+				res.Buf = append(res.Buf, '\\', 'f')
 				res.Width += 2
 				continue
 			case '\n':
 				res.Buf = append(res.Buf, '\\', 'n')
 				res.Width += 2
 				continue
-			case '\\':
-				res.Buf = append(res.Buf, '\\', '\\')
+			case '\r':
+				res.Buf = append(res.Buf, '\\', 'r')
+				res.Width += 2
+				continue
+			case '\t':
+				res.Buf = append(res.Buf, '\\', 't')
 				res.Width += 2
 				continue
 			case '"':
 				res.Buf = append(res.Buf, '\\', '"')
 				res.Width += 2
 				continue
+			case '\\':
+				res.Buf = append(res.Buf, '\\', '\\')
+				res.Width += 2
+				continue
 			}
 		}
 		// handle raw encoding
@@ -386,7 +407,7 @@ func FormatBytes(src []byte, invalid []byte, invalidWidth int, isJSON, isRaw boo
 		default:
 			switch {
 			// escape as \x00
-			case r < ' ':
+			case r < ' ' && !isJSON:
 				res.Buf = append(res.Buf, '\\', 'x', lowerhex[byte(r)>>4], lowerhex[byte(r)&0xf])
 				res.Width += 4
 			// escape as \u0000

fmt_test.go

@@ -1,8 +1,10 @@
 package tblfmt
 
 import (
+	"encoding/json"
 	"reflect"
 	"regexp"
+	"slices"
 	"strconv"
 	"strings"
 	"testing"
@@ -103,6 +105,43 @@ func TestFormatBytesComplex(t *testing.T) {
 	}
 }
 
+func TestFormatJSON(t *testing.T) {
+	s := strings.Join(
+		[]string{
+			"\a",
+			"\b",
+			"\f",
+			"\n",
+			"\r",
+			"\t",
+			"\x1a",
+			"\x2b",
+			"\x3f",
+			"\\",
+			" ",
+			"\x9f",
+			"\xaf",
+			"\xff",
+			"\u1998",
+			"👀",
+			"🤰",
+			"foo",
+		},
+		";",
+	)
+	exp, err := json.Marshal(s)
+	if err != nil {
+		t.Fatalf("expected no error, got: %v", err)
+	}
+	exp = exp[1 : len(exp)-1]
+	t.Logf("exp: %q", string(exp))
+	v := FormatBytes([]byte(s), nil, 0, true, false, 0, 0)
+	t.Logf("v  : %q", v)
+	if b := []byte(v.String()); !slices.Equal(b, exp) {
+		t.Errorf("expected: %q, got: %q", string(exp), string(b))
+	}
+}
+
 func TestFormatBytesRaw(t *testing.T) {
 	tests := []struct {
 		s   string