From 3bb6776880d5f65b65c2f8a33b73ea05ef34115b Mon Sep 17 00:00:00 2001
From: Simon J <simojenki@users.noreply.github.com>
Date: Wed, 25 Aug 2021 09:41:04 +1000
Subject: [PATCH] Distinguish between supported lang and lang in type system
 (#29)

---
 src/i8n.ts        | 22 ++++++++++++----------
 src/sonos.ts      |  3 ++-
 tests/i8n.test.ts |  4 ++--
 3 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/src/i8n.ts b/src/i8n.ts
index 7995859..96168c4 100644
--- a/src/i8n.ts
+++ b/src/i8n.ts
@@ -3,7 +3,8 @@ import { pipe } from "fp-ts/lib/function";
 import { option as O } from "fp-ts";
 import _ from "underscore";
 
-export type LANG = "en-US" | "nl-NL";
+export type LANG = "en-US" | "da-DK" | "de-DE" | "es-ES" | "fr-FR" | "it-IT" | "ja-JP" | "nb-NO" | "nl-NL" | "pt-BR" | "sv-SE" | "zh-CN"
+export type SUPPORTED_LANG = "en-US" | "nl-NL";
 export type KEY =
   | "AppLinkMessage"
   | "artists"
@@ -37,7 +38,7 @@ export type KEY =
   | "loginSuccessful"
   | "loginFailed";
 
-const translations: Record<LANG, Record<KEY, string>> = {
+const translations: Record<SUPPORTED_LANG, Record<KEY, string>> = {
   "en-US": {
     AppLinkMessage: "Linking sonos with $BONOB_SONOS_SERVICE_NAME",
     artists: "Artists",
@@ -107,15 +108,15 @@ const translations: Record<LANG, Record<KEY, string>> = {
 };
 
 const translationsLookup = Object.keys(translations).reduce((lookups, lang) => {
-  lookups.set(lang, translations[lang as LANG]);
-  lookups.set(lang.toLocaleLowerCase(), translations[lang as LANG]);
-  lookups.set(lang.toLocaleLowerCase().split("-")[0]!, translations[lang as LANG]);
+  lookups.set(lang, translations[lang as SUPPORTED_LANG]);
+  lookups.set(lang.toLocaleLowerCase(), translations[lang as SUPPORTED_LANG]);
+  lookups.set(lang.toLocaleLowerCase().split("-")[0]!, translations[lang as SUPPORTED_LANG]);
   return lookups;
 }, new Map<string, Record<KEY, string>>())
 
 export const randomLang = () => _.shuffle(["en-US", "nl-NL"])[0]!;
 
-export const asLANGs = (acceptLanguageHeader: string | undefined) =>
+export const asLANGs = (acceptLanguageHeader: string | undefined): LANG[] =>
   pipe(
     acceptLanguageHeader,
     O.fromNullable,
@@ -125,7 +126,8 @@ export const asLANGs = (acceptLanguageHeader: string | undefined) =>
       pipe(
         it.split(","),
         A.map((it) => it.trim()),
-        A.filter((it) => it != "")
+        A.filter((it) => it != ""),
+        A.map(it => it as LANG)
       )
     ),
     O.getOrElseW(() => [])
@@ -137,12 +139,12 @@ export type Lang = (key: KEY) => string;
 
 export const langs = () => Object.keys(translations);
 
-export const keys = (lang: LANG = "en-US") => Object.keys(translations[lang]);
+export const keys = (lang: SUPPORTED_LANG = "en-US") => Object.keys(translations[lang]);
 
 export default (serviceName: string): I8N =>
   (...langs: string[]): Lang => {
-    const langToUse = 
-      langs.map((l) => translationsLookup.get(l as LANG)).find((it) => it) ||
+    const langToUse =
+      langs.map((l) => translationsLookup.get(l as SUPPORTED_LANG)).find((it) => it) ||
       translations["en-US"];
     return (key: KEY) => {
       const value = langToUse[key]?.replace(
diff --git a/src/sonos.ts b/src/sonos.ts
index be7cde1..e13e765 100644
--- a/src/sonos.ts
+++ b/src/sonos.ts
@@ -7,8 +7,9 @@ import logger from "./logger";
 import { SOAP_PATH, STRINGS_ROUTE, PRESENTATION_MAP_ROUTE } from "./smapi";
 import qs from "querystring";
 import { URLBuilder } from "./url_builder";
+import { LANG } from "./i8n";
 
-export const SONOS_LANG = ["en-US", "da-DK", "de-DE", "es-ES", "fr-FR", "it-IT", "ja-JP", "nb-NO", "nl-NL", "pt-BR", "sv-SE", "zh-CN"]
+export const SONOS_LANG: LANG[] = ["en-US", "da-DK", "de-DE", "es-ES", "fr-FR", "it-IT", "ja-JP", "nb-NO", "nl-NL", "pt-BR", "sv-SE", "zh-CN"]
 
 export const PRESENTATION_AND_STRINGS_VERSION = "21";
 
diff --git a/tests/i8n.test.ts b/tests/i8n.test.ts
index f939dfc..7ac608f 100644
--- a/tests/i8n.test.ts
+++ b/tests/i8n.test.ts
@@ -1,4 +1,4 @@
-import i8n, { langs, LANG, KEY, keys, asLANGs } from "../src/i8n";
+import i8n, { langs, LANG, KEY, keys, asLANGs, SUPPORTED_LANG } from "../src/i8n";
 
 describe("i8n", () => {
   describe("asLANGs", () => {
@@ -41,7 +41,7 @@ describe("i8n", () => {
   describe("validity of translations", () => {
     it("all langs should have same keys as US", () => {
       langs().forEach((l) => {
-        expect(keys(l as LANG)).toEqual(keys("en-US"));
+        expect(keys(l as SUPPORTED_LANG)).toEqual(keys("en-US"));
       });
     });
   });