refactor(utils): categorize functions into separate files (#6773)

packages/docusaurus-utils/src/i18nUtils.ts

@@ -0,0 +1,58 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import path from 'path';
+import _ from 'lodash';
+import type {TranslationFileContent, TranslationFile} from '@docusaurus/types';
+import {DEFAULT_PLUGIN_ID} from './constants';
+
+export function mergeTranslations(
+  contents: TranslationFileContent[],
+): TranslationFileContent {
+  return contents.reduce((acc, content) => ({...acc, ...content}), {});
+}
+
+// Useful to update all the messages of a translation file
+// Used in tests to simulate translations
+export function updateTranslationFileMessages(
+  translationFile: TranslationFile,
+  updateMessage: (message: string) => string,
+): TranslationFile {
+  return {
+    ...translationFile,
+    content: _.mapValues(translationFile.content, (translation) => ({
+      ...translation,
+      message: updateMessage(translation.message),
+    })),
+  };
+}
+
+export function getPluginI18nPath({
+  siteDir,
+  locale,
+  pluginName,
+  pluginId = DEFAULT_PLUGIN_ID,
+  subPaths = [],
+}: {
+  siteDir: string;
+  locale: string;
+  pluginName: string;
+  pluginId?: string | undefined;
+  subPaths?: string[];
+}): string {
+  return path.join(
+    siteDir,
+    'i18n',
+    // namespace first by locale: convenient to work in a single folder for a
+    // translator
+    locale,
+    // Make it convenient to use for single-instance
+    // ie: return "docs", not "docs-default" nor "docs/default"
+    `${pluginName}${pluginId === DEFAULT_PLUGIN_ID ? '' : `-${pluginId}`}`,
+    ...subPaths,
+  );
+}