diff --git a/src/web/app/common/mixins.ls b/src/web/app/common/mixins.ls
index 1194793994..c412e3b322 100644
--- a/src/web/app/common/mixins.ls
+++ b/src/web/app/common/mixins.ls
@@ -12,23 +12,23 @@ module.exports = (me) ~>
 		Cropper: require \cropperjs
 
 	riot.mixin \signout do
-		signout: require './scripts/signout.js'
+		signout: require './scripts/signout'
 
 	riot.mixin \messaging-stream do
 		MessagingStreamConnection: require './scripts/messaging-stream'
 
 	riot.mixin \is-promise do
-		is-promise: require './scripts/is-promise.ls'
+		is-promise: require './scripts/is-promise'
 
 	riot.mixin \get-post-summary do
-		get-post-summary: require './scripts/get-post-summary.js'
+		get-post-summary: require './scripts/get-post-summary'
 
 	riot.mixin \date-stringify do
-		date-stringify: require './scripts/date-stringify.ls'
+		date-stringify: require './scripts/date-stringify'
 
 	riot.mixin \text do
-		analyze: require '../../../common/text/index.js'
-		compile: require './scripts/text-compiler.js'
+		analyze: require '../../../common/text/index'
+		compile: require './scripts/text-compiler'
 
 	riot.mixin \get-password-strength do
 		get-password-strength: require 'syuilo-password-strength'
diff --git a/src/web/app/common/scripts/is-promise.js b/src/web/app/common/scripts/is-promise.js
new file mode 100644
index 0000000000..fd3dc42da3
--- /dev/null
+++ b/src/web/app/common/scripts/is-promise.js
@@ -0,0 +1 @@
+module.exports = x => typeof x.then == 'function';
diff --git a/src/web/app/common/scripts/is-promise.ls b/src/web/app/common/scripts/is-promise.ls
deleted file mode 100644
index e3c7adff85..0000000000
--- a/src/web/app/common/scripts/is-promise.ls
+++ /dev/null
@@ -1 +0,0 @@
-module.exports = (x) -> typeof x.then == \function