First draft of timeout parameter functionality

src/api.test.ts

@@ -227,6 +227,22 @@ describe('makeFetcher', () => {
     })
   })
 
+  it('should accept a timeout in ms', async () => {
+    vi.spyOn(global, 'fetch').mockImplementationOnce(
+      async (_input: URL | RequestInfo, _init?: RequestInit | undefined) => {
+        await new Promise((r) => setTimeout(r, 2000))
+        return new Response(JSON.stringify({ foo: 'bar' }))
+      },
+    )
+    const service = subject.makeFetcher('https://example.com/api', {
+      timeout: 1,
+    })
+    await expect(() =>
+      service('/users', { method: 'post' }).then((r) => r.json()),
+    ).rejects.toThrowError()
+    expect(reqMock).not.toHaveBeenCalled()
+  })
+
   it('should add headers to the request', async () => {
     vi.spyOn(global, 'fetch').mockImplementationOnce(
       successfulFetch({ foo: 'bar' }),

src/api.ts

@@ -110,7 +110,7 @@ function makeFetcher(baseURL: string | URL, baseOptions: BaseOptions = {}) {
     path: T,
     requestInit: EnhancedRequestInit<T> = {},
   ) => {
-    const { headers } = baseOptions
+    const { headers, timeout } = baseOptions
     const requestTransformer = baseOptions.requestTransformer ?? identity
     const responseTransformer = baseOptions.responseTransformer ?? identity
     const headerTransformer = async (ri: EnhancedRequestInit) => ({
@@ -123,10 +123,25 @@ function makeFetcher(baseURL: string | URL, baseOptions: BaseOptions = {}) {
     })
 
     const url = makeGetApiURL(baseURL)(path)
-    const response = await enhancedFetch(
-      url,
-      await headerTransformer(await requestTransformer(requestInit)),
-    )
+    const fetchPromise = async () =>
+      enhancedFetch(
+        url,
+        await headerTransformer(await requestTransformer(requestInit)),
+      )
+
+    const throwOnTimeout = (timeout: number) =>
+      new Promise((_, reject) =>
+        setTimeout(
+          () => reject(new Error(`Timed out (${timeout}ms) fetching ${url}`)),
+          timeout,
+        ),
+      )
+
+    const response = (await (timeout == undefined
+      ? fetchPromise()
+      : Promise.race([fetchPromise(), throwOnTimeout(timeout)]))) as Awaited<
+      ReturnType<typeof fetchPromise>
+    >
     return responseTransformer(response)
   }
 }

src/types.ts

@@ -45,6 +45,7 @@ type BaseOptions = {
   headers?: HeadersInit | (() => HeadersInit | Promise<HeadersInit>)
   requestTransformer?: RequestTransformer
   responseTransformer?: ResponseTransformer
+  timeout?: number
 }
 
 type HTTPMethod = (typeof HTTP_METHODS)[number]