fix(i18next): change how fetchLanguage is implemented (#107)

This is honestly better than a second property on `ClientOptions`.
Another option on `ClientOptions` gets really confusing when you already
have an `i18n` property. Not to mention that other than the type
it wasn't really documented anywhere properly because it was only
being used in `register`.

BREAKING CHANGE: `fetchLanguage` has been moved from `ClientOptions` to `ClientOptions.i18n`

package.json

@@ -26,16 +26,16 @@
 		"@sapphire/prettier-config": "^1.1.6",
 		"@sapphire/ts-config": "^3.0.0",
 		"@sapphire/utilities": "^2.0.1",
-		"@types/jest": "^26.0.23",
+		"@types/jest": "^26.0.24",
 		"@types/node": "^16.4.13",
 		"@types/node-fetch": "^2.5.12",
 		"@types/ws": "^7.4.7",
-		"@typescript-eslint/eslint-plugin": "^4.28.4",
-		"@typescript-eslint/parser": "^4.28.5",
+		"@typescript-eslint/eslint-plugin": "^4.29.1",
+		"@typescript-eslint/parser": "^4.29.1",
 		"cz-conventional-changelog": "^3.3.0",
-		"discord-api-types": "^0.20.2",
-		"discord.js": "dev",
-		"eslint": "^7.31.0",
+		"discord-api-types": "^0.22.0",
+		"discord.js": "^13.0.1",
+		"eslint": "^7.32.0",
 		"eslint-config-prettier": "^8.3.0",
 		"eslint-plugin-prettier": "^3.4.0",
 		"gen-esm-wrapper": "^1.1.2",
@@ -48,7 +48,7 @@
 		"prettier": "^2.3.2",
 		"pretty-quick": "^3.1.1",
 		"ts-jest": "^27.0.4",
-		"ts-node": "^10.1.0",
+		"ts-node": "^10.2.0",
 		"typedoc": "0.19.2",
 		"typedoc-plugin-lerna-packages": "^0.3.1",
 		"typedoc-plugin-nojekyll": "^1.0.1",

packages/i18next/src/lib/InternationalizationHandler.ts

@@ -62,6 +62,10 @@ export class InternationalizationHandler {
 			addPath: this.languagesDirectory,
 			...this.options.backend
 		};
+
+		if (isFunction(this.options.fetchLanguage)) {
+			this.fetchLanguage = this.options.fetchLanguage;
+		}
 	}
 
 	/**

packages/i18next/src/lib/types.ts

@@ -1,3 +1,4 @@
+import type { Awaited } from '@sapphire/utilities';
 import type { Guild, Message, StageChannel, StoreChannel, User, VoiceChannel } from 'discord.js';
 import type { InitOptions } from 'i18next';
 import type { i18nextFsBackend } from 'i18next-fs-backend';
@@ -53,6 +54,17 @@ export interface InternationalizationOptions {
 	 * @since 1.0.0
 	 */
 	defaultNS?: string;
+	/**
+	 * A function that is to be used to retrieve the language for the current context.
+	 * Context exists of a {@link Guild `guild`}, a {@link DiscordChannel `channel`} and a {@link User `user`}.
+	 *
+	 * If this is not set, then the language will always be the default language.
+	 *
+	 * This will be inserted for {@link InternationalizationHandler.fetchLanguage}.
+	 * @since 2.0.0
+	 * @default () => InternationalizationOptions.defaultName
+	 */
+	fetchLanguage?: (context: InternationalizationContext) => Awaited<string | null>;
 }
 
 export type TextBasedDiscordChannel = Message['channel'];
@@ -70,11 +82,4 @@ export interface InternationalizationContext {
 
 export interface InternationalizationClientOptions {
 	i18n?: InternationalizationOptions;
-
-	/**
-	 * Hook that returns the name of a language. Should correspond to {@link InternationalizationHandler.fetchLanguage}.
-	 * @since 1.0.0
-	 * @default () => {@link I18nOptions.defaultName}
-	 */
-	fetchLanguage?: (context: InternationalizationContext) => Promise<string | null> | string | null;
 }

packages/i18next/src/register.ts

@@ -5,7 +5,6 @@ import { InternationalizationClientOptions, InternationalizationHandler } from '
 export class I18nextPlugin extends Plugin {
 	public static [preGenericsInitialization](this: SapphireClient, options: ClientOptions): void {
 		container.i18n = new InternationalizationHandler(options.i18n);
-		if (typeof options.fetchLanguage === 'function') container.i18n.fetchLanguage = options.fetchLanguage;
 	}
 
 	public static async [preLogin](this: SapphireClient): Promise<void> {