core-fetch: baseUrl accepts () => string for lazy resolution

Lets consumers pass `() => import.meta.env.BASE_URL` without orval's CJS
bundle path blowing up on the top-level `import.meta` reference. The
getter is invoked at request time rather than factory time, so the
mutator file can be loaded by orval (which bundles to CJS) without
evaluating `import.meta`.

Closes uwe.admin/webapp-template#21 (scaffold side).

Bump to v0.5.0 — additive change (string form still works) but new
shape for `CoreFetchOptions.baseUrl` is a public API change.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "@uschuster/webapp-scaffold",
-  "version": "0.3.6",
+  "version": "0.5.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@uschuster/webapp-scaffold",
-      "version": "0.3.6",
+      "version": "0.5.0",
       "license": "UNLICENSED",
       "bin": {
         "webapp-scaffold-fetch-openapi": "bin/fetch-openapi.sh",

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@uschuster/webapp-scaffold",
-  "version": "0.4.2",
+  "version": "0.5.0",
   "description": "Shared build scripts + Vite config factories for webapp-template-derived projects.",
   "type": "module",
   "bin": {

src/core-fetch.test.ts

@@ -173,4 +173,23 @@ describe('createCoreFetch — request shape', () => {
         await cf('/v1/x');
         expect(captured).toBe('https://api.example.com/v1/x');
     });
+
+    it('baseUrl getter is resolved at request time, not factory time', async () => {
+        const captured: string[] = [];
+        let dynamicBase = 'https://first.example.com';
+        const cf = createCoreFetch({
+            baseUrl: () => dynamicBase,
+            fetchImpl: ((url: string) => {
+                captured.push(url);
+                return Promise.resolve(jsonResponse({}));
+            }) as unknown as typeof fetch,
+        });
+        await cf('/v1/x');
+        dynamicBase = 'https://second.example.com/';
+        await cf('/v1/y');
+        expect(captured).toEqual([
+            'https://first.example.com/v1/x',
+            'https://second.example.com/v1/y',
+        ]);
+    });
 });

src/core-fetch.ts

@@ -28,8 +28,16 @@ export interface CoreFetchRequest {
 }
 
 export interface CoreFetchOptions {
-    /** Prefix for every request; strip trailing slash. */
-    baseUrl?: string;
+    /**
+     * Prefix for every request; trailing slash stripped at resolve time.
+     *
+     * Accepts a string OR a getter so consumers that derive the base from
+     * `import.meta.env.BASE_URL` (or any other late-bound source) can pass
+     * the getter form. The getter is invoked at request time, never at
+     * factory-construction time — which keeps orval's CJS bundling of the
+     * mutator file from blowing up on top-level `import.meta` references.
+     */
+    baseUrl?: string | (() => string);
 
     /** `'body'` returns the parsed body (default); `'wrapped'` returns { data, status, headers }. */
     responseShape?: ResponseShape;
@@ -97,7 +105,11 @@ export type CoreFetch = CoreFetchWrapped & CoreFetchBody;
 const MUTATING = new Set(['POST', 'PUT', 'PATCH', 'DELETE']);
 
 export function createCoreFetch(opts: CoreFetchOptions = {}): CoreFetch {
-    const base = (opts.baseUrl ?? '').replace(/\/$/, '');
+    // Lazy base resolution — see CoreFetchOptions.baseUrl JSDoc.
+    const resolveBase = (): string => {
+        const raw = typeof opts.baseUrl === 'function' ? opts.baseUrl() : (opts.baseUrl ?? '');
+        return raw.replace(/\/$/, '');
+    };
     // Resolve fetch at call time, not construction time, so tests that
     // `vi.stubGlobal('fetch', ...)` after module import see the stub.
     const callFetch: typeof fetch = opts.fetchImpl
@@ -135,7 +147,7 @@ export function createCoreFetch(opts: CoreFetchOptions = {}): CoreFetch {
 
         let r: Response;
         try {
-            r = await callFetch(`${base}${url}`, {
+            r = await callFetch(`${resolveBase()}${url}`, {
                 credentials: 'include',
                 ...init,
                 headers,