Fix compatibility with CSS Modules

Author: ai

lib/processor.js

@@ -383,8 +383,11 @@ class Processor {
       if (this.disabledValue(decl, result)) return
 
       let unprefixed = this.prefixes.unprefixed(decl.prop)
-      for (let value of this.prefixes.values('add', unprefixed)) {
-        value.process(decl, result)
+      let list = this.prefixes.values('add', unprefixed)
+      if (Array.isArray(list)) {
+        for (let value of list) {
+          if (value.process) value.process(decl, result)
+        }
       }
       Value.save(this.prefixes, decl)
     })
@@ -465,9 +468,8 @@ class Processor {
 
       // Values
       for (let checker of this.prefixes.values('remove', unprefixed)) {
-        if (!checker.check(decl.value)) {
-          continue
-        }
+        if (!checker.check) continue
+        if (!checker.check(decl.value)) continue
 
         unprefixed = checker.unprefixed
         let notHack = this.prefixes.group(decl).down(other => {

test/autoprefixer.test.js

@@ -543,6 +543,10 @@ it('ignores unknown versions on request', () => {
   }).not.toThrow()
 })
 
+it('works with CSS Modules', () => {
+  postcss([autoprefixer()]).process(':export { selectors: _1q6ho_2 }').css
+})
+
 describe('hacks', () => {
   it('ignores prefix IE filter', () => check('filter'))
   it('supports webkit filters', () => check('advanced-filter'))