Enable overriding of language in client twinkle

Per #4 (comment).

language is now part of `Twinkle` object (namespace).

src/Api.ts

@@ -1,5 +1,4 @@
 import { Twinkle } from './twinkle';
-import { language } from './messenger';
 
 /**
  * Wrapper around Morebits.wiki.api that preset the commonly used
@@ -12,8 +11,8 @@ export class Api extends Morebits.wiki.api {
 				action: 'query',
 				format: 'json',
 				formatversion: '2',
-				uselang: language,
-				errorlang: language,
+				uselang: Twinkle.language,
+				errorlang: Twinkle.language,
 				errorsuselocal: true,
 				// tags isn't applicable for all API actions, it gives a warning but that's harmless
 				tags: Twinkle.changeTags,
@@ -38,8 +37,8 @@ export class Api extends Morebits.wiki.api {
 export let mwApi: mw.Api;
 
 /**
- * Called from init(). Can't initialise at top level, since values of language,
- * Twinkle.changeTags and Twinkle.userAgent aren't final by that stage.
+ * Called from init(). Can't initialise at top level, since values of
+ * Twinkle.* aren't final by that stage.
  * @private
  */
 export function initialiseMwApi() {
@@ -48,8 +47,8 @@ export function initialiseMwApi() {
 			action: 'query',
 			format: 'json',
 			formatversion: '2',
-			uselang: language,
-			errorlang: language,
+			uselang: Twinkle.language,
+			errorlang: Twinkle.language,
 			errorsuselocal: true,
 			// tags isn't applicable for all API actions, it gives a warning but that's harmless
 			tags: Twinkle.changeTags,

src/messenger.ts

@@ -15,13 +15,8 @@ import enMessages from '../i18n/en.json';
 export let banana: Banana;
 
 /**
- * The language used for all messages in twinkle-core.
- * This includes interface messages as well as edits made to the wiki.
- * Ideally the interface messages should have been in wgUserLanguage
- * and edits in wgContentLanguage, but this duality is not presently
- * supported.
+ * @deprecated - use {@link Twinkle.language} instead.
  */
-// I believe this is the only use of mw.* at the top level
 export let language = urlParamValue('uselang') || mw.config.get('wgContentLanguage');
 
 let qqxMode: boolean;
@@ -94,7 +89,7 @@ const i18nParserPlugins = {
  * @param messages
  */
 export function addMessages(messages: Messages) {
-	banana.load(messages, language);
+	banana.load(messages, Twinkle.language);
 }
 
 /**
@@ -124,7 +119,7 @@ let EnglishMessagesAvailable = typeof EXCLUDE_ENGLISH_MESSAGES === 'undefined' |
  * Initialize the message store. Called from init.ts.
  */
 export function initMessaging() {
-	banana = new Banana(language);
+	banana = new Banana(Twinkle.language);
 
 	// Register plugins
 	obj_entries(i18nParserPlugins).forEach(([name, plugin]) => {
@@ -136,7 +131,7 @@ export function initMessaging() {
 
 	// QQX is a dummy "language" for documenting messages
 	// No need to load anything when in qqxMode
-	qqxMode = language === 'qqx';
+	qqxMode = Twinkle.language === 'qqx';
 
 	if (qqxMode) {
 		return Promise.resolve();
@@ -146,7 +141,10 @@ export function initMessaging() {
 		banana.load(enMessages, 'en');
 	}
 	const mwMessageList = coreMwMessages.concat(Twinkle.extraMwMessages);
-	return Promise.all([loadMediaWikiMessages(mwMessageList, language), loadTwinkleCoreMessages(language)])
+	return Promise.all([
+		loadMediaWikiMessages(mwMessageList, Twinkle.language),
+		loadTwinkleCoreMessages(Twinkle.language),
+	])
 		.catch((e) => {
 			mw.notify('Failed to load messages needed for Twinkle', { type: 'error' });
 		})
@@ -260,5 +258,5 @@ function initBanana(json) {
  * @deprecated
  */
 export function loadAdditionalMediaWikiMessages(messageList: string[]) {
-	return loadMediaWikiMessages(messageList, language);
+	return loadMediaWikiMessages(messageList, Twinkle.language);
 }

src/twinkle.ts

@@ -1,4 +1,5 @@
 import type { TwinkleModule } from './twinkleModule';
+import { urlParamValue } from './utils';
 
 /**
  * Defined as a namespace: anything that's exported from here (such as
@@ -12,6 +13,15 @@ export namespace Twinkle {
 	 */
 	export let scriptName = 'Twinkle';
 
+	/**
+	 * The language used for all messages in twinkle-core.
+	 * This includes interface messages as well as edits made to the wiki.
+	 * Ideally the interface messages should have been in wgUserLanguage
+	 * and edits in wgContentLanguage, but this duality is not presently
+	 * supported.
+	 */
+	export let language = urlParamValue('uselang') || mw.config.get('wgContentLanguage');
+
 	/**
 	 * User agent
 	 * @see https://meta.wikimedia.org/wiki/User-Agent_policy