Cache mcdata registries

src/app/RegistryFetcher.ts

@@ -1,6 +1,9 @@
 import { CollectionRegistry } from '@mcschema/core'
 import config from '../config.json'
 
+const localStorageCache = (version: string) => `cache_${version}`
+declare var __MCDATA_MASTER_HASH__: string;
+
 const baseUrl = 'https://raw.githubusercontent.com/Arcensoth/mcdata'
 export const mcdata = (ref: string, registry: string) => {
   return `${baseUrl}/${ref}/processed/reports/registries/${registry}/data.min.json`
@@ -9,18 +12,42 @@ export const mcdata = (ref: string, registry: string) => {
 export const RegistryFetcher = async (target: CollectionRegistry, versionId: string) => {
   const version = config.versions.find(v => v.id === versionId)
   if (!version) return
+
+  const cache = JSON.parse(localStorage.getItem(localStorageCache(versionId)) ?? '{}')
+  const cacheValid = version.mcdata_ref !== 'master' || cache.mcdata_hash === __MCDATA_MASTER_HASH__
+  let cacheDirty = false
+
   await Promise.all(config.registries.map(async r => {
     const id = typeof r === 'string' ? r : r.id
+
+    if (!cache.registries) {
+      cache.registries = {}
+    }
+    if (cacheValid && cache.registries?.[id]) {
+      target.register(id, cache.registries[id])
+      return
+    }
+
     const url = typeof r === 'string'
-        ? mcdata(version.mcdata_ref, r)
-        : `${baseUrl}/${version.mcdata_ref}/${r.path}`
+      ? mcdata(version.mcdata_ref, r)
+      : `${baseUrl}/${version.mcdata_ref}/${r.path}`
+
     try {
       const res = await fetch(url)
       const data = await res.json()
-      console.log(r, url, data)
+
       target.register(id, data.values)
+      cache.registries[id] = data.values
+      cacheDirty = true
     } catch (e) {
       console.error(`Error occurred while fetching registry "${id}":`, e)
     }
   }))
+
+  if (cacheDirty) {
+    if (version.mcdata_ref === 'master') {
+      cache.mcdata_hash = __MCDATA_MASTER_HASH__
+    }
+    localStorage.setItem(localStorageCache(versionId), JSON.stringify(cache))
+  }
 }