reencode: Add CompactFloats

4 files changed, 23 insertions, 5 deletions

diff --git a/ReleaseNotes.md b/ReleaseNotes.md
index b1647da..ae147b1 100644
--- a/ReleaseNotes.md
+++ b/ReleaseNotes.md
@@ -4,11 +4,15 @@
 
   User-facing changes:
 
-   - General bugfixes:
+   - General Changes:
 
       + Encoder, ReEncoder: Now correctly trims unnecessary the
         trailing '0's from the fraction-part when compacting numbers.
 
+      + ReEncoder: No longer compact floating-point numbers by
+        default, add a `CompactFloats` ReEncoderConfig option to
+        control this.
+
    - Compatibility bugfixes:
 
       + compat/json.Valid: No longer considers truncated JSON
@@ -17,6 +21,9 @@
       + compat/json.Compact, compat/json.Indent: Don't write to the
         destination buffer if there is a syntax error.
 
+      + compat/json.Compact, compat/json.Indent: No longer compact
+        floating-point numbers; as `encoding/json` doesn't.
+
    - Unicode:
 
       + Feature: Encoder, ReEncoder: Add an `InvalidUTF8`
diff --git a/compat/json/compat_test.go b/compat/json/compat_test.go
index d989a4d..128bd1b 100644
--- a/compat/json/compat_test.go
+++ b/compat/json/compat_test.go
@@ -46,6 +46,7 @@ func TestCompatCompact(t *testing.T) {
 		"trunc":    {In: `{`, Out: ``, Err: `unexpected end of JSON input`},
 		"object":   {In: `{}`, Out: `{}`},
 		"non-utf8": {In: "\"\x85\xcd\"", Out: "\"\x85\xcd\""},
+		"float":    {In: `1.200e003`, Out: `1.200e003`},
 	}
 	for tcName, tc := range testcases {
 		tc := tc
@@ -75,6 +76,7 @@ func TestCompatIndent(t *testing.T) {
 		"trunc":    {In: `{`, Out: ``, Err: `unexpected end of JSON input`},
 		"object":   {In: `{}`, Out: `{}`},
 		"non-utf8": {In: "\"\x85\xcd\"", Out: "\"\x85\xcd\""},
+		"float":    {In: `1.200e003`, Out: `1.200e003`},
 	}
 	for tcName, tc := range testcases {
 		tc := tc
@@ -103,6 +105,7 @@ func TestCompatMarshal(t *testing.T) {
 	testcases := map[string]testcase{
 		"non-utf8": {In: "\x85\xcd", Out: "\"\\ufffd\\ufffd\""},
 		"urc":      {In: "\ufffd", Out: "\"\ufffd\""},
+		"float":    {In: 1.2e3, Out: `1200`},
 	}
 	for tcName, tc := range testcases {
 		tc := tc
diff --git a/reencode.go b/reencode.go
index 1a9999b..1943b9c 100644
--- a/reencode.go
+++ b/reencode.go
@@ -54,6 +54,10 @@ type ReEncoderConfig struct {
 	// this is different than the usual behavior.
 	ForceTrailingNewlines bool
 
+	// CompactFloats causes the *ReEncoder to trim unnecessary '0'
+	// digits from floating-point number values.
+	CompactFloats bool
+
 	// A JSON document is specified to be a sequence of Unicode
 	// codepoints; InvalidUTF8 controls how the *ReEncoder behaves
 	// when it encounters invalid UTF-8 bytes in a JSON string
@@ -109,8 +113,10 @@ func NewReEncoder(out io.Writer, cfg ReEncoderConfig) *ReEncoder {
 	}
 
 	// Numbers
-	module = &reEncodeCompactNum{
-		out: module,
+	if cfg.CompactFloats {
+		module = &reEncodeCompactNum{
+			out: module,
+		}
 	}
 
 	// Strings
diff --git a/reencode_test.go b/reencode_test.go
index bc6d246..715e976 100644
--- a/reencode_test.go
+++ b/reencode_test.go
@@ -135,7 +135,8 @@ func TestReEncode(t *testing.T) {
 		},
 		"numbers": {
 			enc: ReEncoderConfig{
-				Compact: true,
+				Compact:       true,
+				CompactFloats: true,
 			},
 			in: []any{
 				Number("1.200e003"),
@@ -144,7 +145,8 @@ func TestReEncode(t *testing.T) {
 		},
 		"numbers-zero": {
 			enc: ReEncoderConfig{
-				Compact: true,
+				Compact:       true,
+				CompactFloats: true,
 			},
 			in: []any{
 				Number("1.000e000"),