diff --git a/src/web/app/common/mixins.ls b/src/web/app/common/mixins.ls
index 812bcae10..ca27e0357 100644
--- a/src/web/app/common/mixins.ls
+++ b/src/web/app/common/mixins.ls
@@ -21,7 +21,7 @@ module.exports = (me) ~>
 		is-promise: require './scripts/is-promise.ls'
 
 	riot.mixin \get-post-summary do
-		get-post-summary: require './scripts/get-post-summary.ls'
+		get-post-summary: require './scripts/get-post-summary.js'
 
 	riot.mixin \date-stringify do
 		date-stringify: require './scripts/date-stringify.ls'
diff --git a/src/web/app/common/scripts/get-post-summary.js b/src/web/app/common/scripts/get-post-summary.js
new file mode 100644
index 000000000..8e17d54e8
--- /dev/null
+++ b/src/web/app/common/scripts/get-post-summary.js
@@ -0,0 +1,37 @@
+const getPostSummary = post => {
+	let = post.text ? post.text : '';
+
+	// メディアが添付されているとき
+	if (post.media) {
+		summary += ` (${post.media.length}つのメディア)`;
+	}
+
+	// 投票が添付されているとき
+	if (post.poll) {
+		summary += ' (投票)';
+	}
+
+	// 返信のとき
+	if (post.reply_to_id) {
+		if (post.reply_to) {
+			replySummary = getPostSummary(post.reply_to);
+			summary += ` RE: ${replySummary}`;
+		} else {
+			summary += ' RE: ...';
+		}
+	}
+
+	// Repostのとき
+	if (post.repost_id) {
+		if (post.repost) {
+			repostSummary = getPostSummary(post.repost);
+			summary += ` RP: ${repostSummary}`;
+		} else {
+			summary += ' RP: ...';
+		}
+	}
+
+	return summary.trim();
+};
+
+module.exports = getPostSummary;
diff --git a/src/web/app/common/scripts/get-post-summary.ls b/src/web/app/common/scripts/get-post-summary.ls
deleted file mode 100644
index 67178bc32..000000000
--- a/src/web/app/common/scripts/get-post-summary.ls
+++ /dev/null
@@ -1,30 +0,0 @@
-get-post-summary = (post) ~>
-	summary = if post.text? then post.text else ''
-
-	# メディアが添付されているとき
-	if post.media?
-		summary += " (#{post.media.length}つのメディア)"
-
-	# 投票が添付されているとき
-	if post.poll?
-		summary += " (投票)"
-
-	# 返信のとき
-	if post.reply_to_id?
-		if post.reply_to?
-			reply-summary = get-post-summary post.reply_to
-			summary += " RE: #{reply-summary}"
-		else
-			summary += " RE: ..."
-
-	# Repostのとき
-	if post.repost_id?
-		if post.repost?
-			repost-summary = get-post-summary post.repost
-			summary += " RP: #{repost-summary}"
-		else
-			summary += " RP: ..."
-
-	return summary.trim!
-
-module.exports = get-post-summary