@dloizides/api-client-base

Realm-agnostic, product-agnostic HTTP plumbing for the dloizides.com portfolio.

Built for the Questioner / OnlineMenu product split (and any future products): a single fetch wrapper, a uniform error envelope shape, a typed event bus for bridging interceptor-layer signals to UI components, and a declarative error registry that maps HTTP statuses + body codes to UI actions.

This package never references a specific product, realm, or hardcoded URL. Consumers supply their own baseUrl and pair the client with @dloizides/auth-client through the getAccessToken callback — the two packages compose without importing each other.

Install

npm install @dloizides/api-client-base

Quick start

import { ApiClient, ApiError } from '@dloizides/api-client-base';
import { AuthClient } from '@dloizides/auth-client';

const auth = new AuthClient(
  { baseUrl: 'https://identity.example.com', realm: 'questioner', clientId: 'web' },
  storage,
);

const api = new ApiClient({
  baseUrl: 'https://api.questioner.com',
  defaultHeaders: { 'X-Tenant-Id': tenantId },
  getAccessToken: () => auth.getAccessToken(),
});

try {
  const user = await api.get<{ id: string }>('/users/me');
} catch (err) {
  if (err instanceof ApiError && err.status === 401) {
    // token expired — your interceptor or refresh layer handles it
  }
}

What's in the box

Surface	Purpose
ApiClient	fetch-based client. JSON-by-default, throws ApiError on non-2xx.
ApiError / ApiErrorEnvelope	uniform error shape (status, code, message, details).
apiEventBus / ApiEventBus	typed pub/sub bridging interceptor layer to UI.
ErrorActionType / ErrorSeverity	enums for the registry's UI actions.
getErrorRules / registerErrorRule / resetErrorRules	mutable, priority-sorted rule registry.
setLoginRedirectPath / resetLoginRedirectPath	override the session-expired redirect target.
matchError / matchesRule / matchesStatus / matchesPath / matchesMethod	matcher engine.
classifyAxiosError	pure classifier on a duck-typed AxiosErrorLike. No axios dependency.
extractErrorCode / extractErrorMessage / extractRequestId	pure helpers for FastEndpoints / ProblemDetails envelopes.

Composition with @dloizides/auth-client

The getAccessToken callback is the only contract — this package never imports auth-client, and auth-client never imports this package. Wire them up at the application bootstrap:

const auth = new AuthClient({ baseUrl, realm, clientId }, new BrowserStorageTokenStorage());
const api = new ApiClient({
  baseUrl: API_BASE_URL,
  getAccessToken: () => auth.getAccessToken(),
});

Custom error rules

The default registry covers the common HTTP errors (401 session-expired, 402 payment-required modal, 403 forbidden toast, 422 validation, 5xx server errors, etc.). Add app-specific rules at any time:

import {
  registerErrorRule,
  ErrorActionType,
  ErrorSeverity,
  PRIORITY_ROUTE_SPECIFIC,
} from '@dloizides/api-client-base';

registerErrorRule({
  name: 'team-deleted',
  match: { status: 410, path: '/teams' },
  action: {
    type: ErrorActionType.Modal,
    severity: ErrorSeverity.Warning,
    modalComponent: 'TeamDeletedModal',
  },
  messageKey: 'errors.teamDeleted',
  priority: PRIORITY_ROUTE_SPECIFIC,
});

License

MIT © dloizides.com