fix: loader should return empty translations in development

packages/cli/src/api/compile.js

@@ -96,13 +96,17 @@ function processTokens(tokens, arg) {
   )
 }
 
-export function createCompiledCatalog(locale: string, messages: CatalogType) {
+export function createCompiledCatalog(
+  locale: string,
+  messages: CatalogType,
+  strict: boolean = false
+) {
   const [language] = locale.split(/[_-]/)
   const pluralRules = plurals[language]
 
   const compiledMessages = R.keys(messages).map(key => {
-    const translation = messages[key]
-    return t.objectProperty(t.stringLiteral(key), compile(translation || key))
+    const translation = messages[key] || (!strict ? key : "")
+    return t.objectProperty(t.stringLiteral(key), compile(translation))
   })
 
   const languageData = [

packages/loader/src/index.js

@@ -19,5 +19,11 @@ export default function(source) {
     catalogs[locale]
   )
 
-  return createCompiledCatalog(locale, messages)
+  // In production we don't want untranslated strings. It's better to use message
+  // keys as a last resort.
+  // In development, however, we want to catch missing strings with `missing` parameter
+  // of I18nProvider (React) or setupI18n (core) and therefore we need to get
+  // empty translations if missing.
+  const strict = process.env.NODE_ENV !== "production"
+  return createCompiledCatalog(locale, messages, strict)
 }