From 5fdf2454d65795dc259978a67861daa3c267e981 Mon Sep 17 00:00:00 2001
From: Kyo Nagashima <hail2u@gmail.com>
Date: Wed, 16 Mar 2016 10:12:50 +0900
Subject: [PATCH] Ignore var() function on unquoting

The `var()` function of a custom properties should be untouched.

This fixes #70.
---
 index.js                  |  5 +++++
 lib/regexp.js             |  3 +++
 test/expected/issue70.css |  1 +
 test/fixtures/issue70.css | 15 +++++++++++++++
 4 files changed, 24 insertions(+)
 create mode 100644 test/expected/issue70.css
 create mode 100644 test/fixtures/issue70.css

diff --git a/index.js b/index.js
index f76b71b..5f1e7df 100644
--- a/index.js
+++ b/index.js
@@ -57,6 +57,11 @@ var canUnquote = function (str) {
 // Unquote font family name if possible
 var unquoteFontFamily = function (family) {
   var quote;
+
+  if (family.match(re.varFunction)) {
+    return family;
+  }
+
   family = family.replace(re.quotedString, "$2");
   quote = setQuote(RegExp.$1);
 
diff --git a/lib/regexp.js b/lib/regexp.js
index d4cb8eb..168ffde 100644
--- a/lib/regexp.js
+++ b/lib/regexp.js
@@ -77,6 +77,9 @@ re.urlNeedQuote = /[\s()"']/,
 // --valid_prop-name
 re.validProp = /^-{0,2}[^!-,./:-@[-^`{-~]+$/i,
 
+// var(--custom-prop-name)
+re.varFunction = /^var\([\w-]+\)$/i,
+
 //  , \t, \r, \n
 re.whiteSpaces = /\s+/g,
 re.whiteSpacesAfterSymbol = /([(,:])\s/g,
diff --git a/test/expected/issue70.css b/test/expected/issue70.css
new file mode 100644
index 0000000..67a3a4b
--- /dev/null
+++ b/test/expected/issue70.css
@@ -0,0 +1 @@
+:root{--foo:"Foo"}.foo{font-family:var(--foo)}.bar{font-family:Bar,var(--foo),serif}.baz{font-family:"var(--foo)"}
diff --git a/test/fixtures/issue70.css b/test/fixtures/issue70.css
new file mode 100644
index 0000000..59dc5fa
--- /dev/null
+++ b/test/fixtures/issue70.css
@@ -0,0 +1,15 @@
+:root {
+  --foo: "Foo";
+}
+
+.foo {
+  font-family: var(--foo);
+}
+
+.bar {
+  font-family: Bar, var(--foo), serif;
+}
+
+.baz {
+  font-family: "var(--foo)";
+}