From 72452cf42ad8fb23685fc0c9cdfe9f697da7bc84 Mon Sep 17 00:00:00 2001
From: Vincent De Oliveira <vincent@iamvdo.me>
Date: Tue, 30 Jun 2015 18:24:36 +0200
Subject: [PATCH] Fix browsers detection (IEs)

---
 lib/pixrem.js       | 27 +++++++++++++++------------
 spec/pixrem-spec.js |  4 ++--
 2 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/lib/pixrem.js b/lib/pixrem.js
index d048567..2ef8464 100755
--- a/lib/pixrem.js
+++ b/lib/pixrem.js
@@ -34,16 +34,19 @@ Pixrem.prototype.postcss = function (css) {
   var vendor = require('postcss/lib/vendor');
   var browsers = browserslist(_options.browsers);
 
-  // if IE9+
+  // detect IE versions needed
+  var isIElte8, isIEgte9, isIE9_10;
+  if (detectBrowser(browsers, 'ie <= 8')) {
+    isIElte8 = true;
+  }
   if (detectBrowser(browsers, 'ie >= 9')) {
-    // if IE9 or IE10
-    var specialCaseIE = false;
-    if (detectBrowser(browsers, 'ie 9, ie 10')) {
-      specialCaseIE = true;
-    } else {
-      return;
-    }
+    isIEgte9 = true;
+  }
+  if (detectBrowser(browsers, 'ie 9, ie 10')) {
+    isIE9_10 = true;
   }
+  // no IE versions needed, skip
+  if (!isIElte8 && !isIEgte9 && !isIE9_10) { return; }
 
   if (_options.html) {
     // First, check root font-size
@@ -65,7 +68,7 @@ Pixrem.prototype.postcss = function (css) {
   css.eachRule(function (rule) {
 
     // if options.at-rules is false AND it's not IE9-10: skip @rules
-    if (!_options.atrules && !specialCaseIE) {
+    if (!_options.atrules && !isIE9_10) {
       if (rule.type === 'atrule' || (rule.parent && rule.parent.type === 'atrule')) { return; }
     }
 
@@ -79,10 +82,10 @@ Pixrem.prototype.postcss = function (css) {
         var prop = vendor.unprefixed(decl.prop);
         // replace rems only if needed
         var isFontShorthand = (prop === 'font');
-        var isSpecialCaseIE9 = (specialCaseIE && (isPseudoElement || isFontShorthand));
-        var isUseless = (!specialCaseIE && !(_VALUES.test(value) || _PROPS.test(prop)));
+        var isSpecialCaseIE9_10 = (isIE9_10 && (isPseudoElement || isFontShorthand));
+        var isUseless = (!isIE9_10 && !(_VALUES.test(value) || _PROPS.test(prop)));
 
-        if ( isSpecialCaseIE9 || isUseless ) {
+        if ( isSpecialCaseIE9_10 || isUseless ) {
 
           value = value.replace(_remgex, function ($1) {
             // Round decimal pixels down to match webkit and opera behavior:
diff --git a/spec/pixrem-spec.js b/spec/pixrem-spec.js
index e338c38..4c60d73 100644
--- a/spec/pixrem-spec.js
+++ b/spec/pixrem-spec.js
@@ -229,10 +229,10 @@ describe('pixrem', function () {
     expect(processed).toBe(expected);
   });
 
-  it('should not add fallback when IE8 is not in scope', function () {
+  it('should not add fallback when IE8- are not in scope', function () {
     var css = '.rule{width: 2rem}';
     var expected = '.rule{width: 2rem}';
-    var processed = pixrem.process(css, undefined, {browsers: 'last 2 versions'});
+    var processed = pixrem.process(css, undefined, {browsers: 'firefox 28'});
     expect(processed).toBe(expected);
   });