refactor: add func getNlsConfiguration & tests

This PR refactors part of vscode.ts and adds a function to get the NLS
Configuration.

This makes the code more readable and easier to test.

And it adds multiple tests for this part of the codebase.

src/browser/pages/vscode.ts

@@ -5,9 +5,56 @@ const options = getOptions()
 // TODO: Add proper types.
 /* eslint-disable @typescript-eslint/no-explicit-any */
 
-let nlsConfig: any
+// NOTE@jsjoeio
+// This lives here ../../../lib/vscode/src/vs/base/common/platform.ts#L106
+export const nlsConfigElementId = "vscode-remote-nls-configuration"
+
+type NlsConfiguration = {
+  locale: string
+  availableLanguages: { [key: string]: string } | {}
+  _languagePackId?: string
+  _translationsConfigFile?: string
+  _cacheRoot?: string
+  _resolvedLanguagePackCoreLocation?: string
+  _corruptedFile?: string
+  _languagePackSupport?: boolean
+  loadBundle?: any
+}
+
+/**
+ * A helper function to get the NLS Configuration settings.
+ *
+ * This is used by VSCode for localizations (i.e. changing
+ * the display language).
+ *
+ * Make sure to wrap this in a try/catch block when you call it.
+ **/
+export function getNlsConfiguration(document: Document) {
+  const errorMsgPrefix = "[vscode]"
+  const nlsConfigElement = document?.getElementById(nlsConfigElementId)
+  const nlsConfig = nlsConfigElement?.getAttribute("data-settings")
+
+  if (!document) {
+    throw new Error(`${errorMsgPrefix} Could not parse NLS configuration. document is undefined.`)
+  }
+
+  if (!nlsConfigElement) {
+    throw new Error(
+      `${errorMsgPrefix} Could not parse NLS configuration. Could not find nlsConfigElement with id: ${nlsConfigElementId}`,
+    )
+  }
+
+  if (!nlsConfig) {
+    throw new Error(
+      `${errorMsgPrefix} Could not parse NLS configuration. Found nlsConfigElement but missing data-settings attribute.`,
+    )
+  }
+
+  return JSON.parse(nlsConfig) as NlsConfiguration
+}
+
 try {
-  nlsConfig = JSON.parse(document.getElementById("vscode-remote-nls-configuration")!.getAttribute("data-settings")!)
+  const nlsConfig = getNlsConfiguration(document)
   if (nlsConfig._resolvedLanguagePackCoreLocation) {
     const bundles = Object.create(null)
     nlsConfig.loadBundle = (bundle: any, _language: any, cb: any): void => {
@@ -26,10 +73,6 @@ try {
         .catch(cb)
     }
   }
-} catch (error) {
-  /* Probably fine. */
-}
-
   ;(self.require as any) = {
     // Without the full URL VS Code will try to load file://.
     baseUrl: `${window.location.origin}${options.csStaticBase}/lib/vscode/out`,
@@ -47,6 +90,9 @@ try {
     },
     "vs/nls": nlsConfig,
   }
+} catch (error) {
+  console.error(error)
+}
 
 try {
   document.body.style.background = JSON.parse(localStorage.getItem("colorThemeData")!).colorMap["editor.background"]

test/unit/browser/vscode.test.ts

@@ -0,0 +1,61 @@
+/**
+ * @jest-environment jsdom
+ */
+import { JSDOM } from "jsdom"
+import { getNlsConfiguration, nlsConfigElementId } from "../../../src/browser/pages/vscode"
+
+describe("vscode", () => {
+  describe("getNlsConfiguration", () => {
+    beforeEach(() => {
+      const { window } = new JSDOM()
+      global.document = window.document
+    })
+
+    it("should throw an error if Document is undefined", () => {
+      const errorMsgPrefix = "[vscode]"
+      const errorMessage = `${errorMsgPrefix} Could not parse NLS configuration. document is undefined.`
+
+      expect(() => {
+        getNlsConfiguration(undefined as any as Document)
+      }).toThrowError(errorMessage)
+    })
+    it("should throw an error if no nlsConfigElement", () => {
+      const errorMsgPrefix = "[vscode]"
+      const errorMessage = `${errorMsgPrefix} Could not parse NLS configuration. Could not find nlsConfigElement with id: ${nlsConfigElementId}`
+
+      expect(() => {
+        getNlsConfiguration(document)
+      }).toThrowError(errorMessage)
+    })
+    it("should throw an error if no nlsConfig", () => {
+      const mockElement = document.createElement("div")
+      mockElement.setAttribute("id", nlsConfigElementId)
+      document.body.appendChild(mockElement)
+
+      const errorMsgPrefix = "[vscode]"
+      const errorMessage = `${errorMsgPrefix} Could not parse NLS configuration. Found nlsConfigElement but missing data-settings attribute.`
+
+      expect(() => {
+        getNlsConfiguration(document)
+      }).toThrowError(errorMessage)
+
+      document.body.removeChild(mockElement)
+    })
+    it("should return the correct configuration", () => {
+      const mockElement = document.createElement("div")
+      const dataSettings = {
+        first: "Jane",
+        last: "Doe",
+      }
+
+      mockElement.setAttribute("id", nlsConfigElementId)
+      mockElement.setAttribute("data-settings", JSON.stringify(dataSettings))
+      document.body.appendChild(mockElement)
+      const actual = getNlsConfiguration(global.document)
+
+      expect(actual).toStrictEqual(dataSettings)
+
+      document.body.removeChild(mockElement)
+    })
+  })
+})