Add language customization flag (#7374)

This allows you to customize any string (that has a translation) or add your own translations.

test/unit/node/i18n.test.ts

@@ -0,0 +1,154 @@
+import { promises as fs } from "fs"
+import * as os from "os"
+import * as path from "path"
+import { loadCustomStrings } from "../../../src/node/i18n"
+
+describe("i18n", () => {
+  let tempDir: string
+  let validJsonFile: string
+  let invalidJsonFile: string
+  let nonExistentFile: string
+
+  beforeEach(async () => {
+    // Create temporary directory for test files
+    tempDir = await fs.mkdtemp(path.join(os.tmpdir(), "code-server-i18n-test-"))
+
+    // Create test files
+    validJsonFile = path.join(tempDir, "valid.json")
+    invalidJsonFile = path.join(tempDir, "invalid.json")
+    nonExistentFile = path.join(tempDir, "does-not-exist.json")
+
+    // Write valid JSON file
+    await fs.writeFile(
+      validJsonFile,
+      JSON.stringify({
+        WELCOME: "Custom Welcome",
+        LOGIN_TITLE: "My Custom App",
+        LOGIN_BELOW: "Please log in to continue",
+      }),
+    )
+
+    // Write invalid JSON file
+    await fs.writeFile(invalidJsonFile, '{"WELCOME": "Missing closing quote}')
+  })
+
+  afterEach(async () => {
+    // Clean up temporary directory
+    await fs.rmdir(tempDir, { recursive: true })
+  })
+
+  describe("loadCustomStrings", () => {
+    it("should load valid JSON file successfully", async () => {
+      // Should not throw an error
+      await expect(loadCustomStrings(validJsonFile)).resolves.toBeUndefined()
+    })
+
+    it("should throw clear error for non-existent file", async () => {
+      await expect(loadCustomStrings(nonExistentFile)).rejects.toThrow(
+        `Custom strings file not found: ${nonExistentFile}\nPlease ensure the file exists and is readable.`,
+      )
+    })
+
+    it("should throw clear error for invalid JSON", async () => {
+      await expect(loadCustomStrings(invalidJsonFile)).rejects.toThrow(
+        `Invalid JSON in custom strings file: ${invalidJsonFile}`,
+      )
+    })
+
+    it("should handle empty JSON object", async () => {
+      const emptyJsonFile = path.join(tempDir, "empty.json")
+      await fs.writeFile(emptyJsonFile, "{}")
+
+      await expect(loadCustomStrings(emptyJsonFile)).resolves.toBeUndefined()
+    })
+
+    it("should handle nested JSON objects", async () => {
+      const nestedJsonFile = path.join(tempDir, "nested.json")
+      await fs.writeFile(
+        nestedJsonFile,
+        JSON.stringify({
+          WELCOME: "Hello World",
+          NESTED: {
+            KEY: "Value",
+          },
+        }),
+      )
+
+      await expect(loadCustomStrings(nestedJsonFile)).resolves.toBeUndefined()
+    })
+
+    it("should handle special characters and unicode", async () => {
+      const unicodeJsonFile = path.join(tempDir, "unicode.json")
+      await fs.writeFile(
+        unicodeJsonFile,
+        JSON.stringify({
+          WELCOME: "欢迎来到 code-server",
+          LOGIN_TITLE: "Willkommen bei {{app}}",
+          SPECIAL: "Special chars: àáâãäåæçèéêë 🚀 ♠️ ∆",
+        }),
+        "utf8",
+      )
+
+      await expect(loadCustomStrings(unicodeJsonFile)).resolves.toBeUndefined()
+    })
+
+    it("should handle generic errors that are not ENOENT or SyntaxError", async () => {
+      const testFile = path.join(tempDir, "test.json")
+      await fs.writeFile(testFile, "{}")
+
+      // Mock fs.readFile to throw a generic error
+      const originalReadFile = fs.readFile
+      const mockError = new Error("Permission denied")
+      fs.readFile = jest.fn().mockRejectedValue(mockError)
+
+      await expect(loadCustomStrings(testFile)).rejects.toThrow(
+        `Failed to load custom strings from ${testFile}: Permission denied`,
+      )
+
+      // Restore original function
+      fs.readFile = originalReadFile
+    })
+
+    it("should handle errors that are not Error instances", async () => {
+      const testFile = path.join(tempDir, "test.json")
+      await fs.writeFile(testFile, "{}")
+
+      // Mock fs.readFile to throw a non-Error object
+      const originalReadFile = fs.readFile
+      fs.readFile = jest.fn().mockRejectedValue("String error")
+
+      await expect(loadCustomStrings(testFile)).rejects.toThrow(
+        `Failed to load custom strings from ${testFile}: String error`,
+      )
+
+      // Restore original function
+      fs.readFile = originalReadFile
+    })
+
+    it("should handle null/undefined errors", async () => {
+      const testFile = path.join(tempDir, "test.json")
+      await fs.writeFile(testFile, "{}")
+
+      // Mock fs.readFile to throw null
+      const originalReadFile = fs.readFile
+      fs.readFile = jest.fn().mockRejectedValue(null)
+
+      await expect(loadCustomStrings(testFile)).rejects.toThrow(`Failed to load custom strings from ${testFile}: null`)
+
+      // Restore original function
+      fs.readFile = originalReadFile
+    })
+
+    it("should complete without errors for valid input", async () => {
+      const testFile = path.join(tempDir, "resource-test.json")
+      const customStrings = {
+        WELCOME: "Custom Welcome Message",
+        LOGIN_TITLE: "Custom Login Title",
+      }
+      await fs.writeFile(testFile, JSON.stringify(customStrings))
+
+      // Should not throw any errors
+      await expect(loadCustomStrings(testFile)).resolves.toBeUndefined()
+    })
+  })
+})