Refactor: Move the post logic to each plugins

src/general.ts

@@ -106,10 +106,10 @@ export default async (url: URL.Url): Promise<Summary> => {
 	}
 
 	return {
-		title: title,
-		icon: icon,
-		description: description,
-		thumbnail: image,
-		sitename: siteName
+		title: title || null,
+		icon: icon || null,
+		description: description || null,
+		thumbnail: image || null,
+		sitename: siteName || null
 	};
 };

src/index.ts

@@ -64,16 +64,6 @@ export default async (url: string, options: Options): Promise<Result> => {
 		? await match.summary(_url)
 		: await general(_url);
 
-	// Replace '' to null
-	Object.keys(summary).forEach(k => {
-		if (summary[k]) {
-			summary[k] = summary[k].trim();
-			if (summary[k] === '') {
-				summary[k] = null;
-			}
-		}
-	});
-
 	return Object.assign(summary, {
 		url: actualUrl
 	});

src/plugins/amazon.ts

@@ -34,10 +34,10 @@ export async function summary(url: URL.Url) {
 	const thumbnail: string = $('#landingImage').attr('src');
 
 	return {
-		title: title,
+		title: title || null,
 		icon: 'https://www.amazon.com/favicon.ico',
-		description: description,
-		thumbnail: thumbnail,
+		description: description || null,
+		thumbnail: thumbnail || null,
 		sitename: 'Amazon'
 	};
 };