DecodeThenEOF: Simplify

1 files changed, 16 insertions, 22 deletions

diff --git a/decode.go b/decode.go
index 9c05860..1e90bb1 100644
--- a/decode.go
+++ b/decode.go
@@ -122,33 +122,27 @@ func Decode(r interface {
 }
 
 // DecodeThenEOF is like decode, but emits an error if there is extra data after the JSON.
-func DecodeThenEOF(r interface {
-	io.Reader
-	io.RuneScanner
-}, ptr any) error {
-	dec := NewDecoder(r)
+func DecodeThenEOF(r io.Reader, ptr any) error {
+	return NewDecoder(r).DecodeThenEOF(ptr)
+}
+
+func (dec *Decoder) DecodeThenEOF(ptr any) (err error) {
 	if err := dec.Decode(ptr); err != nil {
 		return err
 	}
-	for {
-		c, s, t, _ := dec.io.ReadRuneType()
-		switch t {
-		case RuneTypeSpace:
-			// do nothing
-		case RuneTypeEOF:
-			if s > 0 {
-				return &DecodeError{
-					Err: &DecodeSyntaxError{
-						Err:    fmt.Errorf("invalid character %q after top-level value", c),
-						Offset: dec.InputOffset(),
-					},
-				}
-			}
-			return nil
-		default:
-			panic("should not happen")
+	c, s, t, _ := dec.io.ReadRuneType()
+	if t != RuneTypeEOF {
+		panic("should not happen")
+	}
+	if s > 0 {
+		return &DecodeError{
+			Err: &DecodeSyntaxError{
+				Err:    fmt.Errorf("invalid character %q after top-level value", c),
+				Offset: dec.InputOffset(),
+			},
 		}
 	}
+	return nil
 }
 
 func (dec *Decoder) Decode(ptr any) (err error) {