chore(i18n): migrate i18n.js to TypeScript and add banana-i18n types

tsconfig.json

@@ -21,7 +21,7 @@
         "declaration": true,
         "emitDeclarationOnly": true,
         "outDir": "dist",
-        "declarationMap": true
+        "declarationMap": true,
     },
     "include": [
         "v0/src/**/*.ts",

v1/src/simulator/src/i18n.ts

@@ -0,0 +1,31 @@
+import Banana from 'banana-i18n'
+
+const banana = new Banana()
+
+// window.locale may be undefined; use a string type
+const locale: string = (window as any).locale || 'en'
+
+banana.setLocale(locale)
+
+// fallback language
+const finalFallback = 'en'
+
+// object with default language preloaded
+interface Messages {
+  [key: string]: Record<string, string>
+}
+
+const messages: Messages = {
+  [finalFallback]: require(`./i18n/${finalFallback}.json`),
+}
+
+try {
+  messages[locale] = require(`./i18n/${locale}.json`)
+} catch (err) {
+  // If loading for current locale failed, just fallback
+  console.warn(`Failed to load locale ${locale}, falling back to ${finalFallback}`)
+}
+
+banana.load(messages)
+
+export default banana

v1/src/simulator/src/types/banana-i18n.d.ts

@@ -0,0 +1,9 @@
+declare module 'banana-i18n' {
+  export default class Banana {
+    locale: string
+    constructor(locale?: string)
+    setLocale(locale: string): void
+    get(key: string, params?: any[]): string
+    load(messages: Record<string, Record<string, string>>): void
+  }
+}