handle empty XCardsImage cases

Author: aafeher

extract_test.go

@@ -965,6 +965,10 @@ func TestExtractor_Extract(t *testing.T) {
 					URL:         `https://github.com/aafeher/go-microdata-extract`,
 					Description: `X Cards with image`,
 					XCardsImage: []extract.XCardsImage{
+						{
+							URL:   "",
+							Width: 1200,
+						},
 						{
 							URL: "https://picsum.photos/200/300",
 						},

extractors/xcards.go

@@ -306,6 +306,11 @@ func handleXCardsImageProperty(xc *XCards, parts []string, content string) {
 	}
 	lastIdx := len(xc.XCardsImage) - 1
 
+	if lastIdx < 0 {
+		xc.XCardsImage = append(xc.XCardsImage, XCardsImage{})
+		lastIdx = 0
+	}
+
 	if len(parts) == 2 {
 		xc.XCardsImage[lastIdx].URL = content
 		return

test/test-17-xcards-image.html

@@ -7,6 +7,7 @@
     <meta name="twitter:title" content="go-microdata-extract" />
     <meta name="twitter:url" content="https://github.com/aafeher/go-microdata-extract" />
     <meta name="twitter:description" content="X Cards with image" />
+    <meta name="twitter:image:width" content="1200" />
     <meta name="twitter:image" content="https://picsum.photos/200/300" />
     <meta name="twitter:image" content="https://picsum.photos/210/310" />
     <meta name="twitter:image:secure_url" content="https://picsum.photos/210/310" />