Handle case when meta tags don't exist (#4)

Co-authored-by: JPeer264 <jan.oster94@gmail.com>

index.js

@@ -7,14 +7,24 @@ const prettyMs = require('pretty-ms');
 
 const getMetaTag = (html, property) => {
 	const regex = new RegExp(`<meta[^>]*property=["|']${property}["|'][^>]*>`, 'i');
+	const results = regex.exec(html);
 
-	return regex.exec(html)[0];
+	if (!results) {
+		throw new Error(`Missing ${property}`);
+	}
+
+	return results[0];
 };
 
 const getMetaTagContent = metaTagHtml => {
-	const regex = /content=["]([^"]*)["]/i;
+	const contentRegex = /content=["]([^"]*)["]/i;
+	const results = contentRegex.exec(metaTagHtml);
+
+	if (!results) {
+		throw new Error(`Missing content attribute in ${chalk.bold(metaTagHtml)}`);
+	}
 
-	return regex.exec(metaTagHtml)[1];
+	return results[1];
 };
 
 module.exports = bundler => {
@@ -23,28 +33,41 @@ module.exports = bundler => {
 			return;
 		}
 		console.log('');
+
 		const spinner = ora(chalk.grey('Fixing og:image link')).start();
 		const start = Date.now();
 
 		const htmlPath = path.join(bundler.options.outDir, 'index.html');
 		const html = fs.readFileSync(htmlPath).toString();
+		let hasErrors = false;
 
-		const ogImageTag = getMetaTag(html, 'og:image');
+		try {
-		const ogImageContent = getMetaTagContent(ogImageTag);
+			const ogImageTag = getMetaTag(html, 'og:image');
+			const ogImageContent = getMetaTagContent(ogImageTag);
 
-		const ogUrlTag = getMetaTag(html, 'og:url');
+			const ogUrlTag = getMetaTag(html, 'og:url');
-		const ogUrlContent = getMetaTagContent(ogUrlTag);
+			const ogUrlContent = getMetaTagContent(ogUrlTag);
 
-		const absoluteOgImageUrl = url.resolve(ogUrlContent, ogImageContent);
+			const absoluteOgImageUrl = url.resolve(ogUrlContent, ogImageContent);
-		const ogImageTagAbsoluteUrl = ogImageTag.replace(ogImageContent, absoluteOgImageUrl);
+			const ogImageTagAbsoluteUrl = ogImageTag.replace(ogImageContent, absoluteOgImageUrl);
-		const patchedHtml = html.replace(ogImageTag, ogImageTagAbsoluteUrl);
+			const patchedHtml = html.replace(ogImageTag, ogImageTagAbsoluteUrl);
 
-		fs.writeFileSync(htmlPath, patchedHtml);
+			fs.writeFileSync(htmlPath, patchedHtml);
+		} catch (error) {
+			spinner.fail(error.message);
+
+			hasErrors = true;
+		}
 
 		const end = Date.now();
+		const symbol = hasErrors ? chalk.red('✖') : '✨ ';
+		const text = hasErrors ?
+			chalk.red('Failed to fix og:image link.') :
+			chalk.green(`Fixed og:image link in ${prettyMs(end - start)}.`);
+
 		spinner.stopAndPersist({
-			symbol: '✨ ',
+			symbol,
-			text: chalk.green(`Fixed og:image link in ${prettyMs(end - start)}.`)
+			text
 		});
 	});
 };