feat: Server side translation setup (#4657)

* Server side translation setup

* docs

app/utils/i18n.test.ts

@@ -0,0 +1,92 @@
+import i18n from "i18next";
+import de_DE from "../../shared/i18n/locales/de_DE/translation.json";
+import en_US from "../../shared/i18n/locales/en_US/translation.json";
+import pt_PT from "../../shared/i18n/locales/pt_PT/translation.json";
+import { initI18n } from "./i18n";
+
+describe("i18n env is unset", () => {
+  beforeEach(() => {
+    initI18n()
+      .addResources("en-US", "translation", en_US)
+      .addResources("de-DE", "translation", de_DE)
+      .addResources("pt-PT", "translation", pt_PT);
+  });
+
+  it("translation of key should match", () =>
+    expect(i18n.t("Saving")).toBe("Saving"));
+
+  it("translation if changed to de-DE", () => {
+    i18n.changeLanguage("de-DE");
+    expect(i18n.t("Saving")).toBe("Speichert");
+  });
+
+  it("translation if changed to pt-PT", () => {
+    i18n.changeLanguage("pt-PT");
+    expect(i18n.t("Saving")).toBe("A guardar");
+  });
+});
+describe("i18n env is en-US", () => {
+  beforeEach(() => {
+    initI18n("en-US")
+      .addResources("en-US", "translation", en_US)
+      .addResources("de-DE", "translation", de_DE)
+      .addResources("pt-PT", "translation", pt_PT);
+  });
+
+  it("translation of key should match", () =>
+    expect(i18n.t("Saving")).toBe("Saving"));
+
+  it("translation if changed to de-DE", () => {
+    i18n.changeLanguage("de-DE");
+    expect(i18n.t("Saving")).toBe("Speichert");
+  });
+
+  it("translation if changed to pt-PT", () => {
+    i18n.changeLanguage("pt-PT");
+    expect(i18n.t("Saving")).toBe("A guardar");
+  });
+});
+
+describe("i18n env is de-DE", () => {
+  beforeEach(() => {
+    initI18n("de-DE")
+      .addResources("en-US", "translation", en_US)
+      .addResources("de-DE", "translation", de_DE)
+      .addResources("pt-PT", "translation", pt_PT);
+  });
+
+  it("translation of key should match", () =>
+    expect(i18n.t("Saving")).toBe("Speichert"));
+
+  it("translation if changed to en-US", () => {
+    i18n.changeLanguage("en-US");
+    expect(i18n.t("Saving")).toBe("Saving");
+  });
+
+  it("translation if changed to pt-PT", () => {
+    i18n.changeLanguage("pt-PT");
+    expect(i18n.t("Saving")).toBe("A guardar");
+  });
+});
+
+describe("i18n env is pt-PT", () => {
+  beforeEach(() => {
+    initI18n("pt-PT")
+      .addResources("en-US", "translation", en_US)
+      .addResources("de-DE", "translation", de_DE)
+      .addResources("pt-PT", "translation", pt_PT);
+  });
+
+  it("translation of key should match", () =>
+    expect(i18n.t("Saving")).toBe("A guardar"));
+
+  it("translation if changed to en-US", () => {
+    i18n.changeLanguage("en-US");
+    expect(i18n.t("Saving")).toBe("Saving");
+  });
+
+  it("translation if changed to de-DE", () => {
+    i18n.changeLanguage("de-DE");
+    expect(i18n.t("Saving")).toBe("Speichert");
+  });
+});