diff --git a/src/web/app/common/scripts/date-stringify.js b/src/web/app/common/scripts/date-stringify.js
new file mode 100644
index 0000000000..48e19704d5
--- /dev/null
+++ b/src/web/app/common/scripts/date-stringify.js
@@ -0,0 +1,13 @@
+module.exports = date => {
+	if (typeof date == 'string') date = new Date(date);
+	return (
+		date.getFullYear()  + '年' + 
+		date.getMonth() + 1 + '月' + 
+		date.getDate()      + '日' +
+		' ' +
+		date.getHours()     + '時' + 
+		date.getMinutes()   + '分' + 
+		' ' +
+		`(${['日', '月', '火', '水', '木', '金', '土'][date.getDay()]})`
+	);
+};
diff --git a/src/web/app/common/scripts/date-stringify.ls b/src/web/app/common/scripts/date-stringify.ls
deleted file mode 100644
index 7e85192ce7..0000000000
--- a/src/web/app/common/scripts/date-stringify.ls
+++ /dev/null
@@ -1,14 +0,0 @@
-module.exports = (date) ->
-	if typeof date == \string then date = new Date date
-
-	text =
-		date.get-full-year! + \年 +
-		date.get-month! + 1 + \月 +
-		date.get-date!      + \日 +
-		' ' +
-		date.get-hours!     + \時 +
-		date.get-minutes!   + \分 +
-		' ' +
-		"(#{[\日 \月 \火 \水 \木 \金 \土][date.get-day!]})"
-
-	return text