faster classname function

routes/_components/IconButton.html

@@ -60,16 +60,19 @@
   }
 </style>
 <script>
+
+  import { classname } from '../_utils/classname'
+
   export default {
     computed: {
       computedClass: (pressable, pressed, big, className) => {
-        return [
+        return classname(
           'icon-button',
           !pressable && 'not-pressable',
           pressed && 'pressed',
           big && 'big-icon',
           className
-        ].filter(Boolean).join(' ')
+        )
       }
     }
   }

routes/_components/status/Status.html

@@ -94,6 +94,7 @@
   import { store } from '../../_store/store'
   import { goto } from 'sapper/runtime.js'
   import { registerClickDelegate, unregisterClickDelegate } from '../../_utils/delegate'
+  import { classname } from '../../_utils/classname'
 
   export default {
     oncreate() {
@@ -124,11 +125,11 @@
     store: () => store,
     helpers: {
       getClasses(originalStatus, timelineType, isStatusInOwnThread) {
-        return [
+        return classname(
           originalStatus.visibility === 'direct' && 'status-direct',
           timelineType !== 'search' && 'status-in-timeline',
           isStatusInOwnThread && 'status-in-own-thread'
-        ].filter(Boolean).join(' ')
+        )
       }
     },
     methods: {

routes/_utils/classname.js

@@ -0,0 +1,15 @@
+export function classname () {
+  let res = ''
+  let len = arguments.length
+  let i = -1
+  while (++i < len) {
+    let item = arguments[i]
+    if (item) {
+      if (res) {
+        res += ' '
+      }
+      res += item
+    }
+  }
+  return res
+}