From 8cee316877d65ec8c1e57bee2e25630db0cad1fa Mon Sep 17 00:00:00 2001
From: Fathy Boundjadj <fathy.boundjadj@gmail.com>
Date: Wed, 4 Jul 2018 22:29:28 +0200
Subject: [PATCH] Use user installation of `cssnano` (#1432)

---
 src/transforms/postcss.js | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/transforms/postcss.js b/src/transforms/postcss.js
index 90898e807d6..370935674c3 100644
--- a/src/transforms/postcss.js
+++ b/src/transforms/postcss.js
@@ -1,7 +1,7 @@
 const localRequire = require('../utils/localRequire');
 const loadPlugins = require('../utils/loadPlugins');
 const postcss = require('postcss');
-const cssnano = require('cssnano');
+const semver = require('semver');
 
 module.exports = async function(asset) {
   let config = await getConfig(asset);
@@ -49,14 +49,18 @@ async function getConfig(asset) {
   }
 
   if (asset.options.minify) {
+    let [cssnano, {version}] = await Promise.all(
+      ['cssnano', 'cssnano/package.json'].map(name =>
+        localRequire(name, asset.name).catch(() => require(name))
+      )
+    );
     config.plugins.push(
       cssnano(
         (await asset.getConfig(['cssnano.config.js'])) || {
-          // Only enable safe css transforms by default.
+          // Only enable safe css transforms if cssnano < 4
           // See: https://github.com/parcel-bundler/parcel/issues/698
-          // Note: Remove when upgrading cssnano to v4
           // See: https://github.com/ben-eb/cssnano/releases/tag/v4.0.0-rc.0
-          safe: true
+          safe: semver.satisfies(version, '<4.0.0-rc')
         }
       )
     );