feat: add getLocaleList api in geo module [ROW-569] (#220)

* add new api in geo module - getLocaleList

* remove unused imports

* refactor api output

* add readme

* Create fluffy-ways-sing.md

Author: Divyansh Singh

.changeset/fluffy-ways-sing.md

@@ -0,0 +1,5 @@
+---
+"@razorpay/i18nify-js": patch
+---
+
+feat: add getLocaleList api in geo module

packages/i18nify-js/README.md

@@ -760,6 +760,22 @@ console.log(res);
 */
 ```
 
+#### getLocaleList()
+
+🌐 This function fetches a comprehensive mapping of country codes to their supported locale codes. It's your go-to tool for discovering which locales are available for each country! The function returns a promise that resolves to an object where each key is a country code, and its value is an array of supported locale codes.
+
+```javascript
+const locales = await getLocaleList();
+console.log(locales);
+/* Output:
+{
+  "IN": ["hi_IN", "en_IN"],
+  "US": ["en_US"],
+  // ... other countries and their locales
+}
+*/
+```
+
 #### getLocaleByCountry
 
 The getLocaleByCountry API is your multilingual compass, helping you discover all the supported locales for any country. Perfect for building apps that need to handle multiple language variants within a single country, it returns an array of locale codes that are officially used in the specified country.

packages/i18nify-js/src/modules/geo/__tests__/getLocaleList.test.ts

@@ -0,0 +1,77 @@
+import getLocaleList from '../getLocaleList';
+import { I18NIFY_DATA_SOURCE } from '../../shared';
+
+describe('getLocaleList', () => {
+  const mockResponse = {
+    metadata_information: {
+      IN: {
+        locales: {
+          hi_IN: { name: 'Hindi' },
+          en_IN: { name: 'English' },
+        },
+      },
+      US: {
+        locales: {
+          en_US: { name: 'English' },
+        },
+      },
+    },
+  };
+
+  beforeEach(() => {
+    global.fetch = jest.fn(() =>
+      Promise.resolve({
+        json: () => Promise.resolve(mockResponse),
+      }),
+    ) as jest.Mock;
+  });
+
+  afterEach(() => {
+    jest.resetAllMocks();
+  });
+
+  it('fetches all locales successfully', async () => {
+    const localeList = await getLocaleList();
+    expect(global.fetch).toHaveBeenCalledWith(
+      `${I18NIFY_DATA_SOURCE}/country/metadata/data.json`,
+    );
+    expect(localeList).toEqual({
+      IN: ['hi_IN', 'en_IN'],
+      US: ['en_US'],
+    });
+  });
+
+  it('handles API errors correctly', async () => {
+    const errorMessage = 'Network error';
+    global.fetch = jest.fn(() =>
+      Promise.reject(new Error(errorMessage)),
+    ) as jest.Mock;
+
+    await expect(getLocaleList()).rejects.toThrow(
+      `An error occurred while fetching country metadata. The error details are: ${errorMessage}.`,
+    );
+  });
+
+  it('handles empty response data', async () => {
+    global.fetch = jest.fn(() =>
+      Promise.resolve({
+        json: () => Promise.resolve({ metadata_information: {} }),
+      }),
+    ) as jest.Mock;
+
+    const localeList = await getLocaleList();
+    expect(localeList).toEqual({});
+  });
+
+  it('handles malformed response data', async () => {
+    global.fetch = jest.fn(() =>
+      Promise.resolve({
+        json: () => Promise.resolve({ invalid_key: {} }),
+      }),
+    ) as jest.Mock;
+
+    await expect(getLocaleList()).rejects.toThrow(
+      'An error occurred while fetching country metadata.',
+    );
+  });
+});

packages/i18nify-js/src/modules/geo/getLocaleList.ts

@@ -0,0 +1,30 @@
+import { withErrorBoundary } from '../../common/errorBoundary';
+import { I18NIFY_DATA_SOURCE } from '../shared';
+
+/**
+ * Retrieves the list of locales for a country or all countries
+ *
+ * This function makes a network request to central i18nify-data source and
+ * returns a promise for the locales of a country or all countries
+ *
+ * @param {CountryCodeType} [countryCode] - Optional country code to get locales for a specific country
+ * @returns {Promise} Promise object containing locale information
+ */
+const getLocaleList = (): Promise<Record<string, string[]>> => {
+  return fetch(`${I18NIFY_DATA_SOURCE}/country/metadata/data.json`)
+    .then((res) => res.json())
+    .then((res) => {
+      const allLocales: Record<string, string[]> = {};
+      Object.keys(res.metadata_information).forEach((code) => {
+        allLocales[code] = Object.keys(res.metadata_information[code].locales);
+      });
+      return allLocales;
+    })
+    .catch((err) => {
+      throw new Error(
+        `An error occurred while fetching country metadata. The error details are: ${err.message}.`,
+      );
+    });
+};
+
+export default withErrorBoundary<typeof getLocaleList>(getLocaleList);

packages/i18nify-js/src/modules/geo/index.ts

@@ -6,4 +6,5 @@ export { default as getCities } from './getCities';
 export { default as getZipcodes } from './getZipcodes';
 export { default as getByCountry } from './getByCountry';
 export { default as getDefaultLocaleByCountry } from './getDefaultLocaleByCountry';
+export { default as getLocaleList } from './getLocaleList';
 export { default as getLocaleByCountry } from './getLocaleByCountry';