feat: OmitEmpty() omits zero-length slices and maps

alecthomas · Feb 19, 2024 · 3d05a48 · 3d05a48
1 parent 437c372
commit 3d05a48
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Showing 2 changed files with 14 additions and 2 deletions.
diff --git a/repr.go b/repr.go
@@ -256,11 +256,14 @@ func (p *Printer) reprValue(seen map[reflect.Value]bool, v reflect.Value, indent
 					continue
 				}
 				f := v.Field(i)
+				ft := f.Type()
 				// skip private fields
 				if p.ignorePrivate && !f.CanInterface() {
 					continue
 				}
-				if p.omitEmpty && f.IsZero() {
+				if p.omitEmpty && (f.IsZero() ||
+					ft.Kind() == reflect.Slice && f.Len() == 0 ||
+					ft.Kind() == reflect.Map && f.Len() == 0) {
 					continue
 				}
 				if previous && p.indent == "" {

diff --git a/repr_test.go b/repr_test.go
@@ -48,6 +48,15 @@ func TestReprEmptyArray(t *testing.T) {
 	equal(t, "[]string{}", String([]string{}, OmitEmpty(false)))
 }
 
+func TestReprEmptySliceMapFields(t *testing.T) {
+	v := struct {
+		S  []string
+		M  map[string]string
+		NZ []string
+	}{[]string{}, map[string]string{}, []string{"a", "b"}}
+	equal(t, `struct { S []string; M map[string]string; NZ []string }{NZ: []string{"a", "b"}}`, String(v, OmitEmpty(true)))
+}
+
 func TestReprStringArray(t *testing.T) {
 	equal(t, "[]string{\"a\", \"b\"}", String([]string{"a", "b"}))
 }
@@ -174,7 +183,7 @@ type intSliceStruct struct{ f []int }
 func TestReprEmptySliceStruct(t *testing.T) {
 	a := intSliceStruct{f: []int{}}
 	s := String(a)
-	equal(t, "repr.intSliceStruct{f: []int{}}", s)
+	equal(t, "repr.intSliceStruct{}", s)
 }
 
 func TestReprNilSliceStruct(t *testing.T) {