From 4a4d9a08d5e2badca7bd44675f05014bbfb0c1df Mon Sep 17 00:00:00 2001
From: Steve Repsher <steverep@users.noreply.github.com>
Date: Thu, 5 Oct 2023 10:26:15 -0400
Subject: [PATCH] Load Intl locale data in parallel (#18120)

* Load Intl locale data in parallel

* Switch to check result.ok
---
 src/resources/locale-data-polyfill.ts | 92 +++++++++------------------
 1 file changed, 29 insertions(+), 63 deletions(-)

diff --git a/src/resources/locale-data-polyfill.ts b/src/resources/locale-data-polyfill.ts
index e408947a65..b1de492df7 100644
--- a/src/resources/locale-data-polyfill.ts
+++ b/src/resources/locale-data-polyfill.ts
@@ -1,70 +1,36 @@
 // Loads the static locale data for a given language from FormatJS
 // Parents need to load polyfills first; they are not imported here to avoid a circular reference
 
-const loadedPolyfillLocale = new Set();
+const INTL_POLYFILLS = [
+  "DateTimeFormat",
+  "DisplayNames",
+  "ListFormat",
+  "NumberFormat",
+  "RelativeTimeFormat",
+] as const satisfies readonly (keyof typeof Intl)[];
 
-export const polyfillLocaleData = async (language: string) => {
-  if (loadedPolyfillLocale.has(language)) {
-    return;
-  }
-  loadedPolyfillLocale.add(language);
-  try {
-    if (
-      Intl.NumberFormat &&
-      // @ts-ignore
-      typeof Intl.NumberFormat.__addLocaleData === "function"
-    ) {
-      const result = await fetch(
-        `${__STATIC_PATH__}locale-data/intl-numberformat/${language}.json`
-      );
-      // @ts-ignore
-      Intl.NumberFormat.__addLocaleData(await result.json());
+const loadedLocales: Set<string> = new Set();
+
+const addData = async (
+  obj: (typeof INTL_POLYFILLS)[number],
+  language: string
+) => {
+  // Add function will only exist if constructor is polyfilled
+  if (typeof (Intl[obj] as any)?.__addLocaleData === "function") {
+    const result = await fetch(
+      `${__STATIC_PATH__}locale-data/intl-${obj.toLowerCase()}/${language}.json`
+    );
+    // Ignore if polyfill data does not exist for language
+    if (result.ok) {
+      (Intl[obj] as any).__addLocaleData(await result.json());
     }
-    if (
-      Intl.RelativeTimeFormat &&
-      // @ts-ignore
-      typeof Intl.RelativeTimeFormat.__addLocaleData === "function"
-    ) {
-      const result = await fetch(
-        `${__STATIC_PATH__}locale-data/intl-relativetimeformat/${language}.json`
-      );
-      // @ts-ignore
-      Intl.RelativeTimeFormat.__addLocaleData(await result.json());
-    }
-    if (
-      Intl.DateTimeFormat &&
-      // @ts-ignore
-      typeof Intl.DateTimeFormat.__addLocaleData === "function"
-    ) {
-      const result = await fetch(
-        `${__STATIC_PATH__}locale-data/intl-datetimeformat/${language}.json`
-      );
-      // @ts-ignore
-      Intl.DateTimeFormat.__addLocaleData(await result.json());
-    }
-    if (
-      Intl.DisplayNames &&
-      // @ts-ignore
-      typeof Intl.DisplayNames.__addLocaleData === "function"
-    ) {
-      const result = await fetch(
-        `${__STATIC_PATH__}locale-data/intl-displaynames/${language}.json`
-      );
-      // @ts-ignore
-      Intl.DisplayNames.__addLocaleData(await result.json());
-    }
-    if (
-      Intl.ListFormat &&
-      // @ts-ignore
-      typeof Intl.ListFormat.__addLocaleData === "function"
-    ) {
-      const result = await fetch(
-        `${__STATIC_PATH__}locale-data/intl-listformat/${language}.json`
-      );
-      // @ts-ignore
-      Intl.ListFormat.__addLocaleData(await result.json());
-    }
-  } catch (e) {
-    // Ignore
   }
 };
+
+export const polyfillLocaleData = async (language: string) => {
+  if (loadedLocales.has(language)) {
+    return;
+  }
+  loadedLocales.add(language);
+  await Promise.all(INTL_POLYFILLS.map((obj) => addData(obj, language)));
+};