update docs

1 files changed, 4 insertions, 3 deletions

diff --git a/skate/map.go b/skate/map.go
index 094d3e2..1d6bc0b 100644
--- a/skate/map.go
+++ b/skate/map.go
@@ -42,11 +42,12 @@ type Mapper func([]byte) ([][]byte, error)
 
 // AsTSV serializes the result of a field mapper as TSV. This is a slim
 // adapter, e.g. to parallel.Processor, which expects this function signature.
-// If the last byte of the last field is not a newline, it will be appended.
+// A newline will be appended, if not there already.
 func (f Mapper) AsTSV(p []byte) ([]byte, error) {
 	var (
 		fields [][]byte
 		err    error
+		b      []byte
 	)
 	if fields, err = f(p); err != nil {
 		return nil, err
@@ -54,14 +55,14 @@ func (f Mapper) AsTSV(p []byte) ([]byte, error) {
 	if len(fields) == 0 {
 		return nil, nil
 	}
-	b := bytes.Join(fields, bTab)
+	b = bytes.Join(fields, bTab)
 	if len(b) > 0 && !bytes.HasSuffix(b, bNewline) {
 		b = append(b, bNewline...)
 	}
 	return b, nil
 }
 
-// WithPrefix adds a given prefix to the first element.
+// WithPrefix is a "mapper middleware", adding a given prefix to the first field.
 func WithPrefix(f Mapper, prefix string) Mapper {
 	return func(p []byte) ([][]byte, error) {
 		fields, err := f(p)