From 6573f51e9b817db0c77f158945572f4ba14c71fc Mon Sep 17 00:00:00 2001
From: Christian Kaisermann <christian@kaisermann.me>
Date: Wed, 20 Nov 2019 22:20:15 -0300
Subject: [PATCH] =?UTF-8?q?perf:=20=E2=9A=A1=EF=B8=8F=20delay=20the=20$loa?=
 =?UTF-8?q?ding=20state=20change=20for=20quick=20loadings?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/client/includes/loaderQueue.ts | 26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)

diff --git a/src/client/includes/loaderQueue.ts b/src/client/includes/loaderQueue.ts
index 25bfb87..7cd16d5 100644
--- a/src/client/includes/loaderQueue.ts
+++ b/src/client/includes/loaderQueue.ts
@@ -1,7 +1,11 @@
 import merge from 'deepmerge'
 
 import { LocaleLoader } from '../types'
-import { hasLocaleDictionary, $dictionary } from '../stores/dictionary'
+import {
+  hasLocaleDictionary,
+  $dictionary,
+  addMessagesTo,
+} from '../stores/dictionary'
 import { getCurrentLocale } from '../stores/locale'
 import { $loading } from '../stores/loading'
 
@@ -45,13 +49,6 @@ export function addLoaderToQueue(locale: string, loader: LocaleLoader) {
 }
 
 export async function flushQueue(locale: string = getCurrentLocale()) {
-  if (locale == null) {
-    throw new Error(
-      `[svelte-i18n] Invalid locale into "waitLocale": ${JSON.stringify(
-        locale
-      )}`
-    )
-  }
   if (!hasLocaleQueue(locale)) return
 
   // get queue of XX-YY and XX locales
@@ -59,7 +56,7 @@ export async function flushQueue(locale: string = getCurrentLocale()) {
   if (queue.length === 0) return
 
   removeLocaleFromQueue(locale)
-  $loading.set(true)
+  const loadingDelay = setTimeout(() => $loading.set(true), 200)
 
   // todo what happens if some loader fails?
   return Promise.all(queue.map(loader => loader()))
@@ -67,13 +64,12 @@ export async function flushQueue(locale: string = getCurrentLocale()) {
       partials = partials.map(partial => partial.default || partial)
 
       removeFromLookupCache(locale)
-
-      $dictionary.update(d => {
-        d[locale] = merge.all<any>([d[locale] || {}].concat(partials))
-        return d
-      })
+      addMessagesTo(locale, ...partials)
+    })
+    .then(() => {
+      clearTimeout(loadingDelay)
+      $loading.set(false)
     })
-    .then(() => $loading.set(false))
 }
 
 export function registerLocaleLoader(locale: string, loader: LocaleLoader) {