Upgrade memdown from ~3.0.0 to ~4.0.0

Author: vweevers

package.json

@@ -16,7 +16,7 @@
   "dependencies": {
     "level-js": "~4.0.0",
     "level-packager": "~5.0.0",
-    "memdown": "~3.0.0",
+    "memdown": "~4.0.0",
     "tempy": "^0.2.1",
     "uuid": "^3.3.2",
     "xtend": "~4.0.0"

wrap.js

@@ -25,7 +25,7 @@ module.exports = function (getDown, getLocation, clean) {
       opts = xtend(defaults, opts)
 
       if (defaults.mem) {
-        var location = ''
+        var location = null
       } else {
         location = getLocation()
         if (opts.clean !== false) clean(location, down)