Throw for missing params in localized pathnames

Author: amannn

packages/next-intl/src/navigation/utils.tsx

@@ -106,8 +106,9 @@ export function compileLocalizedPathname<Locales extends AllLocales, Pathname>({
   function compilePath(
     namedPath: Pathnames<Locales>[keyof Pathnames<Locales>]
   ) {
-    let compiled =
+    const template =
       typeof namedPath === 'string' ? namedPath : namedPath[locale];
+    let compiled = template;
 
     if (params) {
       Object.entries(params).forEach(([key, value]) => {
@@ -122,6 +123,15 @@ export function compileLocalizedPathname<Locales extends AllLocales, Pathname>({
       });
     }
 
+    if (process.env.NODE_ENV !== 'production' && compiled.includes('[')) {
+      // Next.js throws anyway, therefore better provide a more helpful error message
+      throw new Error(
+        `Insufficient params provided for localized pathname.\nTemplate: ${template}\nParams: ${JSON.stringify(
+          params
+        )}`
+      );
+    }
+
     if (query) {
       compiled += serializeSearchParams(query);
     }

packages/next-intl/test/navigation/utils.test.tsx

@@ -1,5 +1,8 @@
 import {describe, expect, it} from 'vitest';
-import {serializeSearchParams} from '../../src/navigation/utils';
+import {
+  compileLocalizedPathname,
+  serializeSearchParams
+} from '../../src/navigation/utils';
 
 describe('serializeSearchParams', () => {
   it('handles strings', () => {
@@ -18,3 +21,24 @@ describe('serializeSearchParams', () => {
     expect(serializeSearchParams({v: ['a', 'b']})).toEqual('?v=a&v=b');
   });
 });
+
+describe('compileLocalizedPathname', () => {
+  it('throws when params were not resolved', () => {
+    const locales: ReadonlyArray<string> = ['en'];
+    expect(() =>
+      // @ts-expect-error -- Purposefully miss a param
+      compileLocalizedPathname<typeof locales, '/test/[one]/[two]'>({
+        locale: 'en',
+        pathname: '/test/[one]/[two]',
+        pathnames: '/test/[one]/[two]',
+        params: {one: '1'}
+      })
+    ).toThrow(
+      [
+        'Insufficient params provided for localized pathname.',
+        'Template: /test/[one]/[two]',
+        'Params: {"one":"1"}'
+      ].join('\n')
+    );
+  });
+});