adds jsonwriter

adapters/writers/jsonwriter/jsonwriter.go

@@ -0,0 +1,47 @@
+package jsonwriter
+
+import (
+	"context"
+	"encoding/json"
+	"io"
+
+	"github.com/gosom/scrapemate"
+)
+
+var _ scrapemate.ResultWriter = (*jsonWriter)(nil)
+
+type jsonWriter struct {
+	enc *json.Encoder
+}
+
+func NewJSONWriter(w io.Writer) scrapemate.ResultWriter {
+	enc := json.NewEncoder(w)
+	return &jsonWriter{enc: enc}
+}
+
+func (c *jsonWriter) Run(_ context.Context, in <-chan scrapemate.Result) error {
+	for result := range in {
+		items := asSlice(result.Data)
+
+		for i := range items {
+			if err := c.enc.Encode(items[i]); err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
+
+func asSlice(t any) []any {
+	isSlice, ok := t.([]any)
+	if ok {
+		return isSlice
+	}
+
+	var elements []any
+
+	elements = append(elements, t)
+
+	return elements
+}