initial commit

lib/client.ts

@@ -0,0 +1,26 @@
+/* Browser-side fetch helper for the JSON API. */
+
+export class ApiError extends Error {
+  constructor(
+    public status: number,
+    message: string,
+    public details?: unknown
+  ) {
+    super(message);
+  }
+}
+
+export async function api<T = unknown>(url: string, init?: RequestInit & { json?: unknown }): Promise<T> {
+  const { json, ...rest } = init ?? {};
+  const res = await fetch(url, {
+    ...rest,
+    headers: json !== undefined ? { "content-type": "application/json", ...rest.headers } : rest.headers,
+    body: json !== undefined ? JSON.stringify(json) : rest.body,
+  });
+  const data = await res.json().catch(() => ({}));
+  if (!res.ok) {
+    const details = Array.isArray(data.details) ? `: ${data.details.join("; ")}` : "";
+    throw new ApiError(res.status, (data.error ?? res.statusText) + details, data.details);
+  }
+  return data as T;
+}