From 9387215d6fe7bbaaf3a18ef43021ae81b42cf720 Mon Sep 17 00:00:00 2001
From: Kengo Hamasaki <k.hamasaki@gmail.com>
Date: Thu, 23 Nov 2017 06:22:44 -0800
Subject: [PATCH] fix: allow less which is empty or comments only (#151)

fixes #132
---
 src/style/less/index.js      |  4 ++--
 test/expects/empty-less.css  |  3 +++
 test/expects/empty-less.js   |  3 +++
 test/fixtures/empty-less.vue | 14 ++++++++++++++
 test/test.js                 |  3 ++-
 5 files changed, 24 insertions(+), 3 deletions(-)
 create mode 100644 test/expects/empty-less.css
 create mode 100644 test/expects/empty-less.js
 create mode 100644 test/fixtures/empty-less.vue

diff --git a/src/style/less/index.js b/src/style/less/index.js
index 41054a9..85e086a 100644
--- a/src/style/less/index.js
+++ b/src/style/less/index.js
@@ -19,8 +19,8 @@ export default async function (style, options) {
     )
 
     style.$compiled = {
-        code: css.toString(),
-        map: map.toString()
+        code: css && css.toString() || '',
+        map: map && map.toString() || ''
     }
 
     return style
diff --git a/test/expects/empty-less.css b/test/expects/empty-less.css
new file mode 100644
index 0000000..aa4e5f2
--- /dev/null
+++ b/test/expects/empty-less.css
@@ -0,0 +1,3 @@
+/*# sourceMappingURL=empty-less.vue.map */
+
+/*# sourceMappingURL=empty-less.vue.map */
diff --git a/test/expects/empty-less.js b/test/expects/empty-less.js
new file mode 100644
index 0000000..b6188c0
--- /dev/null
+++ b/test/expects/empty-less.js
@@ -0,0 +1,3 @@
+var emptyLess = { template: "<div class=\"goodbye\"></div>",};
+
+export default emptyLess;
diff --git a/test/fixtures/empty-less.vue b/test/fixtures/empty-less.vue
new file mode 100644
index 0000000..72c221f
--- /dev/null
+++ b/test/fixtures/empty-less.vue
@@ -0,0 +1,14 @@
+<template>
+<div class="goodbye"></div>
+</template>
+
+<script>
+export default {}
+</script>
+
+<style lang="less">
+</style>
+
+<style lang="less">
+// Empty essentially
+</style>
diff --git a/test/test.js b/test/test.js
index 4afa7f6..0a4bd71 100644
--- a/test/test.js
+++ b/test/test.js
@@ -67,7 +67,8 @@ function test(name) {
                 'style',
                 'stylus',
                 'external-script',
-                'postcss'
+                'postcss',
+                'empty-less'
             ].indexOf(name) > -1) {
                 var css = read('expects/' + name + '.css')
                 assert.equal(css.trim(), actualCss.trim(), 'should output style tag content')