clean repeatable issue

WRITEUP.md

@@ -0,0 +1,86 @@
+## Summary
+
+When enabling the allowJs option in the tsconfig.json, the tests fail with the following error:
+
+```less
+✖ 0479083575 to be parsed to a valid number (0.881922ms)
+  TypeError [Error]: Cannot read properties of undefined (reading 'hasOwnProperty')
+      at isSupportedCountry (/path/to/project/node_modules/.pnpm/[email protected]/node_modules/libphonenumber-js/source/metadata.js:510:28)
+      at new PhoneNumberMatcher (/path/to/project/node_modules/.pnpm/[email protected]/node_modules/libphonenumber-js/source/PhoneNumberMatcher.js:157:49)
+      at findPhoneNumbersInText (/path/to/project/node_modules/.pnpm/[email protected]/node_modules/libphonenumber-js/source/findPhoneNumbersInText.js:6:18)
+      at call (/path/to/project/node_modules/.pnpm/[email protected]/node_modules/libphonenumber-js/min/index.cjs.js:14:14)
+      at findPhoneNumbersInText (/path/to/project/node_modules/.pnpm/[email protected]/node_modules/libphonenumber-js/min/index.cjs.js:63:9)
+      at TestContext.<anonymous> (/path/to/project/test/test-file.test.ts:10:24)
+```
+
+## Steps to Reproduce
+
+1. Set up a TypeScript project with the following tsconfig.json
+
+```json
+{
+  "compilerOptions": {
+    "allowJs": true,
+    "outDir": "dist",
+    "moduleResolution": "node16",
+    "esModuleInterop": true,
+    "strict": false,
+    "resolveJsonModule": true
+  }
+}
+```
+
+2. Install libphonenumber-js (version: 1.11.15).
+3. Create the following test file:
+
+```typescript
+import { expect } from "expect";
+import { describe, it } from "node:test";
+import { findPhoneNumbersInText } from "libphonenumber-js";
+
+const tests = ["0479083575"];
+describe("findPhoneNumbersInText", async () => {
+  for (const item of tests) {
+    it(`${item} to be parsed to a valid number`, async () => {
+      const [parsed] = findPhoneNumbersInText(item, "AU");
+      expect(parsed).toEqual(
+        expect.objectContaining({
+          endsAt: 10,
+          startsAt: 0,
+          number: expect.objectContaining({
+            country: "AU",
+            number: "+61479083575",
+          }),
+        })
+      );
+    });
+  }
+});
+```
+
+4. Run the test using node:test or any compatible runner.
+
+## Expected Behaviour
+
+The test should parse the phone number correctly, returning a valid result.
+
+## Actual Behaviour
+
+The test fails with a `TypeError`:
+
+```javacript
+TypeError [Error]: Cannot read properties of undefined (reading 'hasOwnProperty')
+```
+
+## Additional Context
+
+- This issue is not present when `allowJs` is disabled in tsconfig.json.
+- The error originates in the isSupportedCountry method from the metadata.js file in libphonenumber-js.
+- The problem seems to be related to the interaction between the library's code and the TypeScript configuration when JavaScript files are allowed.
+
+## Environment
+
+- libphonenumber-js version: 1.11.15
+- Node.js version: 22.x
+- TypeScript version: 5.x
+- Test Runner: node:test