Code refactored

Should have any problems now with undefined or invalid fields.

Markdown Item URI.js

@@ -1,24 +1,29 @@
 {
-"translatorID":"8dbf9b92-f796-4153-8f2e-ac6c157500dc",
-"translatorType":2,
-"label":"Markdown Item URI",
-"creator":"Silent",
-"target":"markdown",
-"minVersion":"2.0",
-"maxVersion":"",
-"priority":200,
-"inRepository":false,
-"lastUpdated":"2020-10-13"
-}
-
-
-function doExport() {
-	var item;
-	while(item = Zotero.nextItem()) {
-
-		Zotero.write("["+item.creators[0].lastName+". "+item.date+". *"+ item["title"] + "*]")
-		Zotero.write("(zotero://select/items/");
-		var library_id = item.libraryID ? item.libraryID : 0;
-		Zotero.write(library_id+"_"+item.key+")");
+	"translatorID":"8dbf9b92-f796-4153-8f2e-ac6c157500dc",
+	"translatorType":2,
+	"label":"Markdown Item URI",
+	"creator":"Silent",
+	"target":"markdown",
+	"minVersion":"2.0",
+	"maxVersion":"",
+	"priority":200,
+	"inRepository":false,
+	"lastUpdated":"2020-10-15"
 	}
-}
+
+
+	function doExport() {
+		var item;
+		while(item = Zotero.nextItem()) {
+			var date = new Date(item.date).getFullYear()
+
+			var year = date && !isNaN(date) ? date + ". " : (typeof item.date == 'undefined'?  "" : item.date + ". ");
+			var library_id = item.libraryID ? item.libraryID : "";
+			var author_lastname = item.creators[0].lastName ? item.creators[0].lastName + ". " : "";
+			var title = item.title ? "*" + item.title + "*" : "";
+			var key = item.key;
+
+			Zotero.write(`[${author_lastname}${year}${title}](zotero://select/items/${library_id}_${key})`)
+		}
+	}
+