extract auth to lib

src/api/createApiClient.ts

@@ -0,0 +1,134 @@
+export type RequestOptions = {
+  method?: 'GET' | 'POST' | 'PUT' | 'DELETE';
+  token?: string | null;
+  body?: unknown;
+};
+
+export type ResolveErrorInput = {
+  code?: string;
+  status?: number;
+  fallbackMessage?: string;
+};
+
+export type CreateApiClientConfig = {
+  baseUrl: string;
+  resolveError?: (input: ResolveErrorInput) => string;
+  inferErrorCodeFromStatus?: (status?: number | null) => string | undefined;
+  fetchImpl?: typeof fetch;
+};
+
+export class ApiError extends Error {
+  status: number;
+  code?: string;
+  requestId?: string;
+  details?: unknown;
+  rawMessage?: string;
+
+  constructor({
+    message,
+    status,
+    code,
+    requestId,
+    details,
+    rawMessage
+  }: {
+    message: string;
+    status: number;
+    code?: string;
+    requestId?: string;
+    details?: unknown;
+    rawMessage?: string;
+  }) {
+    super(message);
+    this.name = 'ApiError';
+    this.status = status;
+    this.code = code;
+    this.requestId = requestId;
+    this.details = details;
+    this.rawMessage = rawMessage;
+  }
+}
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+  return typeof value === 'object' && value != null;
+}
+
+function parseErrorPayload(data: unknown) {
+  if (!isRecord(data)) {
+    return {
+      code: undefined as string | undefined,
+      rawMessage: undefined as string | undefined,
+      requestId: undefined as string | undefined,
+      details: undefined as unknown
+    };
+  }
+
+  const code = typeof data.code === 'string' ? data.code : undefined;
+  const rawMessage = typeof data.error === 'string' ? data.error : undefined;
+  const requestId = typeof data.requestId === 'string' ? data.requestId : undefined;
+  const details = data.details;
+
+  return { code, rawMessage, requestId, details };
+}
+
+function defaultResolveError({ status, fallbackMessage }: ResolveErrorInput): string {
+  if (fallbackMessage) {
+    return fallbackMessage;
+  }
+
+  if (status != null) {
+    return `Request failed (${status}).`;
+  }
+
+  return 'Request failed. Please try again.';
+}
+
+export function createApiClient(config: CreateApiClientConfig) {
+  const {
+    baseUrl,
+    resolveError = defaultResolveError,
+    inferErrorCodeFromStatus,
+    fetchImpl
+  } = config;
+
+  async function request<T>(path: string, options: RequestOptions = {}): Promise<T> {
+    const { method = 'GET', token, body } = options;
+    const runFetch = fetchImpl ?? fetch;
+
+    const response = await runFetch(`${baseUrl}${path}`, {
+      method,
+      headers: {
+        'Content-Type': 'application/json',
+        ...(token ? { Authorization: `Bearer ${token}` } : {})
+      },
+      body: body ? JSON.stringify(body) : undefined
+    });
+
+    const data = await response.json().catch(() => null);
+
+    if (!response.ok) {
+      const parsed = parseErrorPayload(data);
+      const code = parsed.code ?? inferErrorCodeFromStatus?.(response.status);
+      const message = resolveError({
+        code,
+        status: response.status,
+        fallbackMessage: parsed.rawMessage
+      });
+
+      throw new ApiError({
+        message,
+        status: response.status,
+        code,
+        requestId: parsed.requestId,
+        details: parsed.details,
+        rawMessage: parsed.rawMessage
+      });
+    }
+
+    return data as T;
+  }
+
+  return {
+    request
+  };
+}