axios-retryer/dist/plugins/TokenRefreshPlugin.d.ts

TypeScript-first Axios retry library with concurrency limits, request priority, token refresh, response caching, and circuit breaker plugins.

import { AxiosRequestConfig, AxiosError, AxiosInstance } from 'axios';

declare const AXIOS_RETRYER_REQUEST_PRIORITIES: {
    readonly CRITICAL: 4;
    readonly HIGHEST: 3;
    readonly HIGH: 2;
    readonly MEDIUM: 1;
    readonly LOW: 0;
};
type AxiosRetryerRequestPriority = (typeof AXIOS_RETRYER_REQUEST_PRIORITIES)[keyof typeof AXIOS_RETRYER_REQUEST_PRIORITIES];

type RetryEventArgs<TEvents extends object, K extends keyof TEvents> = NonNullable<TEvents[K]> extends (...args: infer TArgs) => unknown ? TArgs : never;
type RetryEventListener<TEvents extends object, K extends keyof TEvents> = (...args: RetryEventArgs<TEvents, K>) => void;
/**
 * Terminal request error payload emitted by `onRequestError`.
 */
interface AxiosRetryerRequestErrorEvent {
    /** Final Axios error object that caused request failure. */
    error: AxiosError;
    /** Final Axios request config that failed. */
    config: AxiosRequestConfig;
    /** HTTP status if available, otherwise `null` for network-level failures. */
    status: number | null;
    /** Request identifier if available. */
    requestId?: string;
    /** Total attempts performed including the initial attempt. */
    attempts: number;
    /** Whether the final error shape is considered retryable by the active strategy. */
    retryable: boolean;
}
/**
 * Queue-entry payload emitted by `onRequestQueued`.
 */
interface AxiosRetryerRequestQueuedEvent {
    /** Request identifier generated or assigned by RetryManager. */
    requestId: string;
    /** Request config entering the queue. */
    config: AxiosRequestConfig;
    /** Resolved priority used for queue ordering. */
    priority: AxiosRetryerRequestPriority;
    /** Queue size immediately after this request was enqueued. */
    queueSize: number;
}
/**
 * Queue-dispatch payload emitted by `onRequestDispatched`.
 */
interface AxiosRetryerRequestDispatchedEvent {
    /** Request identifier generated or assigned by RetryManager. */
    requestId: string;
    /** Request config dispatched from the queue. */
    config: AxiosRequestConfig;
    /** Resolved priority used for queue ordering. */
    priority: AxiosRetryerRequestPriority;
    /** Time spent waiting in the queue before dispatch (milliseconds). */
    queuedForMs: number;
}
/**
 * Success payload emitted by `onRequestSucceeded`.
 */
interface AxiosRetryerRequestSucceededEvent {
    /** Request identifier generated or assigned by RetryManager. */
    requestId?: string;
    /** Final request config that succeeded. */
    config: AxiosRequestConfig;
    /** Final HTTP status code. */
    status: number;
    /** Total attempts performed including the initial attempt. */
    attempts: number;
}
/**
 * Core events exposed by RetryManager without any plugins attached.
 */
interface CoreRetryEvents {
    /**
     * Triggered when the retry process begins.
     */
    onRetryProcessStarted?: () => void;
    /**
     * Triggered before each retry attempt.
     * @param config The Axios request configuration being retried.
     */
    beforeRetry?: (config: AxiosRequestConfig) => void;
    /**
     * Triggered after a retry attempt.
     * @param config The Axios request configuration being retried.
     * @param success Whether the retry was successful.
     * @param error If the retry failed, the error that caused the failure.
     */
    afterRetry?: (config: AxiosRequestConfig, success: boolean, error?: AxiosError) => void;
    /**
     * Triggered when a retry is scheduled and waiting for the specified delay.
     * @param delayMs The delay in milliseconds.
     * @param config The Axios request configuration.
     */
    onRetryScheduled?: (delayMs: number, config: AxiosRequestConfig) => void;
    /**
     * Triggered for each failed retry attempt.
     * @param config The failed Axios request configuration.
     */
    onFailure?: (config: AxiosRequestConfig) => void;
    /**
     * Triggered when a request enters the queue.
     *
     * @param payload Queue entry metadata for this request.
     */
    onRequestQueued?: (payload: AxiosRetryerRequestQueuedEvent) => void;
    /**
     * Triggered when a queued request is dispatched from the queue to the network layer.
     *
     * @param payload Dispatch metadata including queue wait duration.
     */
    onRequestDispatched?: (payload: AxiosRetryerRequestDispatchedEvent) => void;
    /**
     * Triggered when a request succeeds (initial attempt or after retries).
     *
     * @param payload Success metadata for this request.
     */
    onRequestSucceeded?: (payload: AxiosRetryerRequestSucceededEvent) => void;
    /**
     * Triggered once when a request fails terminally (all retries exhausted or no-retry terminal path).
     * Unlike `onFailure`, this event is emitted only for the final failure.
     *
     * @param payload Terminal error context for application-level handling.
     */
    onRequestError?: (payload: AxiosRetryerRequestErrorEvent) => void;
    /**
     * Triggered when all retries are completed.
     */
    onRetryProcessFinished?: () => void;
    /**
     * Triggered when an in-flight retry delay timer is cancelled — either because
     * the user aborted the request (`source: 'user'`) or because the system shut
     * the request down (`source: 'system'`, e.g. plugin destroy, queue clear).
     */
    onRetryTimerCancelled?: (payload: {
        requestId: string;
        source: 'user' | 'system';
    }) => void;
    /**
     * Triggered when a request cancelled.
     * @param requestId Id of the cancelled request.
     */
    onRequestCancelled?: (requestId: string) => void;
    /**
     * Called when a request fails due to network or connection issues, meaning
     * no valid server response was received (e.g., user is offline).
     *
     * @param request - The Axios request config that encountered a connection error.
     */
    onInternetConnectionError?: (request: AxiosRequestConfig) => void;
    /**
     * Triggered when a blocking request (at or above `blockingPriorityThreshold`) fails terminally.
     * Only fires when `blockingPriorityThreshold` is configured.
     *
     * @param config The Axios request config of the failed blocking request.
     */
    onBlockingRequestFailed?: (config: AxiosRequestConfig) => void;
    /**
     * Triggered when every in-flight blocking request (at or above `blockingPriorityThreshold`)
     * has **succeeded** (terminal success) and none remain in the internal blocker set.
     * Not emitted when a blocker fails (`onBlockingRequestFailed`) or is cancelled.
     * Only fires when `blockingPriorityThreshold` is configured.
     */
    onAllBlockingRequestsResolved?: () => void;
}
type RetryManagerEvents<TPluginEvents extends object = Record<never, never>> = {
    [K in keyof CoreRetryEvents | keyof TPluginEvents]: K extends keyof TPluginEvents ? K extends keyof CoreRetryEvents ? CoreRetryEvents[K] & TPluginEvents[K] : TPluginEvents[K] : K extends keyof CoreRetryEvents ? CoreRetryEvents[K] : never;
};

/**
 * Represents the distribution of different error types encountered
 */
interface ErrorTypesDistribution {
    /** Number of network-related errors (e.g., connection failures) */
    network: number;
    /** Number of 5xx server errors */
    server5xx: number;
    /** Number of 4xx client errors */
    client4xx: number;
    /** Number of canceled requests */
    cancelled: number;
}
/**
 * Represents metrics for a specific request priority level
 */
interface PriorityMetrics {
    /** The priority level (higher numbers indicate higher priority) */
    priority: number;
    /** Total number of retry attempts for this priority */
    total: number;
    /** Number of successful retries for this priority */
    successes: number;
    /** Number of failed retries for this priority */
    failures: number;
    /** Success rate percentage for this priority (0-100) */
    successRate: number;
    /** Failure rate percentage for this priority (0-100) */
    failureRate: number;
}
/**
 * AxiosRetryer detailed metrics
 * */
interface AxiosRetryerDetailedMetrics {
    /** Total number of requests made through the retryer */
    totalRequests: number;
    /** Number of successfully completed retries */
    successfulRetries: number;
    /** Number of failed retry attempts */
    failedRetries: number;
    /** Requests that failed all retry attempts */
    completelyFailedRequests: number;
    /** Requests canceled before completion */
    canceledRequests: number;
    /** Critical priority requests that failed all retries */
    completelyFailedCriticalRequests: number;
    /** Distribution of error types encountered */
    errorTypesDistribution: ErrorTypesDistribution;
    /** Distribution of retry attempts across all requests */
    retryAttemptsDistribution: Record<number, number>;
    /** Count of requests by priority level */
    requestCountsByPriority: Record<number, number>;
    /** Average time spent in queue (seconds) */
    avgQueueWait: number;
    /** Average delay between retry attempts (seconds) */
    avgRetryDelay: number;
    /** Detailed metrics grouped by request priority */
    priorityMetrics: PriorityMetrics[];
    /** Timer health and accumulation metrics */
    timerHealth: {
        /** Number of active internal timers */
        activeTimers: number;
        /** Number of active retry timers */
        activeRetryTimers: number;
        /** Health score (0 = excellent, 100+ = potential issues) */
        healthScore: number;
    };
}
/**
 * Interface for pluggable metrics recording.
 * The core library ships with no-op metrics by default.
 * Use MetricsPlugin for full metrics collection.
 */
interface MetricsRecorder {
    reset(): void;
    buildDetailedMetrics(timerStats: {
        activeTimers: number;
        activeRetryTimers: number;
    }): AxiosRetryerDetailedMetrics;
    emitMetricsUpdated?(): void;
}

/**
 * Logger interface used by RetryManager and its collaborators.
 * Supply a custom implementation via {@link RetryManagerOptions.logger}
 * to redirect or suppress log output.
 */
interface Logger {
    log(message: string, data?: unknown): void;
    error(message: string, error?: unknown): void;
    warn(message: string, data?: unknown): void;
    debug(message: string, meta?: unknown): void;
}
/**
 * Context object passed to plugins during initialization and teardown.
 * Provides the plugin-facing view of RetryManager capabilities including
 * plugin-only wiring hooks that are not part of the public manager API.
 */
interface PluginContext<TPluginEvents extends object = Record<never, never>> {
    /** The Axios instance managed by RetryManager. */
    readonly axiosInstance: AxiosInstance;
    /** Returns the configured logger. */
    getLogger(): Logger;
    /** Subscribe to a manager or plugin event. */
    on<K extends keyof RetryManagerEvents<TPluginEvents>>(event: K, listener: RetryEventListener<RetryManagerEvents<TPluginEvents>, K>): void;
    /** Unsubscribe from a manager or plugin event. */
    off<K extends keyof RetryManagerEvents<TPluginEvents>>(event: K, listener: RetryEventListener<RetryManagerEvents<TPluginEvents>, K>): boolean;
    /** Fire all listeners registered for this event. */
    emit<K extends keyof RetryManagerEvents<TPluginEvents>>(event: K, ...args: RetryEventArgs<RetryManagerEvents<TPluginEvents>, K>): void;
    /**
     * Identical to `emit` — fires all listeners registered for this event.
     *
     * Kept for backward compatibility with existing plugins. There is no semantic
     * distinction from `emit`: prefer `emit` in new code.
     */
    triggerAndEmit<K extends keyof RetryManagerEvents<TPluginEvents>>(event: K, ...args: RetryEventArgs<RetryManagerEvents<TPluginEvents>, K>): void;
    /** Cancel a specific in-flight or queued request by its ID. */
    cancelRequest(requestId: string): void;
    /** Cancel all active and queued requests. */
    cancelAllRequests(): void;
    /** Cancel only requests currently waiting in the queue. */
    cancelQueuedRequests(): void;
    /**
     * Register a queue gate that must approve each request before it is dispatched.
     * Used by plugins that need to block request processing under certain conditions.
     */
    registerQueueGate(name: string, canProcess: (request: AxiosRequestConfig) => boolean): void;
    /** Remove a previously registered queue gate. */
    unregisterQueueGate(name: string): boolean;
    /** Trigger a queue drain pass. Useful after a gate condition changes. */
    refreshQueue(): void;
    /**
     * Register or unregister a metrics recorder.
     * Pass `null` to detach. Used by MetricsPlugin to expose metric data to the RetryManager's getMetrics() method.
     */
    registerMetricsRecorder(recorder: MetricsRecorder | null): void;
    /**
     * Return active timer counts.
     * Used by MetricsPlugin to populate the timerHealth section of detailed metrics.
     */
    getTimerStats(): {
        activeTimers: number;
        activeRetryTimers: number;
    };
    /**
     * Release lifecycle tracking for a request config and mark its queue slot complete.
     * Used by TokenRefreshPlugin when a tracked request is intercepted for token refresh.
     */
    releaseRequestTracking(config: AxiosRequestConfig): void;
}
/**
 * AxiosRetryer plugin interface that can be attached with {@link RetryManager.use} and removed with {@link RetryManager.unuse}
 * */
interface RetryPlugin<TPluginEvents extends object = Record<never, never>> {
    /**
     * Plugin name. Should be unique
     * */
    name: string;
    /**
     * Plugin version (e.g. 1.0.0)
     * */
    version: string;
    /**
     * Phantom covariant marker for TypeScript to infer `TPluginEvents` at call sites
     * such as `manager.use(plugin)`. Never set this at runtime; implementations may
     * simply omit it (it is always `undefined`).
     * */
    readonly _events?: Readonly<TPluginEvents>;
    /**
     * Called when the plugin is attached and initialized.
     * @param context Plugin context providing manager capabilities and plugin-only wiring hooks.
     * */
    initialize: (context: PluginContext<TPluginEvents>) => void;
    /**
     * Called before the plugin is removed.
     * @param context Plugin context providing manager capabilities and plugin-only wiring hooks.
     * */
    onBeforeDestroyed?: (context: PluginContext<TPluginEvents>) => void;
}

interface TokenRefreshResult {
    /**
     * New access token. When `null` or `undefined` (or omitted), the plugin treats the refresh as a no-op:
     * no header update, no `onTokenRefreshed` / `onTokenRefreshFailed`, and no “failed refresh” short-circuit.
     * Concurrent waiters are released without forcing `TokenRefreshFailedError`.
     */
    token?: string | null;
}
type TokenRefreshHandler = (axiosInst: AxiosInstance) => Promise<TokenRefreshResult>;
interface TokenRefreshPluginEvents {
    onTokenRefreshed?: (newToken: string) => void;
    onTokenRefreshFailed?: () => void;
    onBeforeTokenRefresh?: () => void;
}
interface TokenRefreshPluginOptions {
    /** If true, allow multiple refresh attempts up to maxRefreshAttempts on failure. */
    retryOnRefreshFail?: boolean;
    /** Maximum number of refresh attempts (1 => 1 total attempt, 2 => 2 attempts, etc.). */
    maxRefreshAttempts?: number;
    /** Timeout in ms for each refresh call. */
    refreshTimeout?: number;
    /** The HTTP header name to set with the new token (e.g. "Authorization"). */
    authHeaderName?: string;
    /** A prefix for your token (commonly "Bearer "). */
    tokenPrefix?: string;
    /** HTTP status codes that trigger a token refresh (e.g., [401, 419]). */
    refreshStatusCodes?: readonly number[];
    /**
     * Maximum backoff delay in ms between refresh retry attempts.
     * Caps the exponential backoff to prevent multi-minute stalls with high maxRefreshAttempts.
     * Default: 30_000 (30 seconds).
     */
    maxRefreshBackoffMs?: number;
    /**
     * Maximum number of requests that may queue while a token refresh is in flight.
     * Excess requests reject with TokenRefreshQueueOverflowError. Default: 500.
     * Set to 0 or a negative number to disable the cap (not recommended).
     */
    maxQueuedRequests?: number;
    /**
     * Optional function to detect auth errors in response bodies (for APIs that return 200 with error in body)
     * Return true if response contains an auth error that should trigger token refresh
     */
    customErrorDetector?: (response: unknown) => boolean;
}

/**
 * A RetryPlugin that manages token refresh on certain status codes (e.g., 401).
 * It intercepts failed requests, attempts to refresh the token,
 * and re-dispatches any queued requests if refresh succeeds.
 *
 * Can also detect custom auth errors in response bodies for APIs that return 200 OK
 * with error messages in the body (like GraphQL).
 */
declare class TokenRefreshPlugin implements RetryPlugin<TokenRefreshPluginEvents> {
    name: string;
    version: string;
    readonly _events?: Readonly<TokenRefreshPluginEvents>;
    private context;
    private requestInterceptorId;
    private interceptorId;
    private responseInterceptorId;
    private refreshAxios;
    private isRefreshing;
    private refreshQueue;
    private readonly teardown;
    private timerManager;
    private failedAuthHeaderValue;
    private readonly refreshToken;
    private readonly options;
    private logger;
    constructor(refreshToken: TokenRefreshHandler, options?: TokenRefreshPluginOptions);
    /**
     * Called by RetryManager when we register this plugin via manager.use(plugin).
     * Attaches a response interceptor to the manager's axios instance and
     * creates a dedicated axios instance for refresh calls.
     */
    initialize(context: PluginContext<TokenRefreshPluginEvents>): void;
    /**
     * Called when the plugin is removed.
     */
    onBeforeDestroyed(context: PluginContext<TokenRefreshPluginEvents>): void;
    private withTeardown;
    private ensureActive;
    private bindRefreshErrorToRequest;
    /**
     * Returns true when the queue is at or above `maxQueuedRequests`.
     * A value <= 0 disables the cap.
     */
    private isQueueOverflowing;
    private buildQueueOverflowError;
    private rejectQueueEntryWithBoundError;
    private dispose;
    /**
     * Checks successful responses for custom auth errors in the response body
     */
    private handleSuccessResponse;
    /**
     * Intercepts a failed response. If the error status is refreshable and the request
     * hasn't already been retried, then either queues the request (if refresh is in progress)
     * or starts a new refresh cycle.
     */
    private handleResponseError;
    /**
     * Checks if the error status code is in the list of refreshable status codes.
     */
    private isRefreshableError;
    /**
     * Main token refresh flow:
     *  1) Set isRefreshing = true.
     *  2) Attempt to refresh the token.
     *  3) On success, update the auth header and retry both queued and original requests.
     *  4) On failure, clear the queue and reject.
     */
    private handleTokenRefresh;
    /**
     * Attempts token refresh up to maxRefreshAttempts times if retryOnRefreshFail is true.
     * Each attempt is subject to a timeout defined in refreshTimeout. Throw a non-Axios
     * error from the refresh handler to stop remaining refresh retries immediately, for
     * example when no refresh token is available in storage.
     */
    private executeTokenRefresh;
    /**
     * Updates the manager's default auth header so subsequent requests automatically carry the new token.
     */
    private updateAuthHeader;
    /**
     * Retries the given request through the retry manager pipeline,
     * marking it with __isRetryRefreshRequest to avoid loops.
     */
    private retryRequest;
    /**
     * If a 401 is encountered while a refresh is already in progress, queue the request.
     */
    private queueRefreshRequest;
    private flushQueuedWithToken;
    /**
     * When the refresh handler opts out (`token` null/undefined), release waiters without treating refresh as failed.
     */
    private flushQueuedAfterSkippedRefresh;
    /**
     * If the token refresh fails completely, reject all queued requests and emit an event.
     * @returns The logical refresh failure error — callers must wrap with `bindRefreshErrorToRequest`
     *          for the initiating request so RetryManager receives `config`.
     */
    private handleRefreshFailure;
}

declare class AxiosRetryerError extends Error {
    readonly code: string;
    constructor(message: string, code: string);
}

declare class MissingTokenRefreshHandlerError extends AxiosRetryerError {
    constructor(message?: string);
}

declare class TokenRefreshTimeoutError extends AxiosRetryerError {
    readonly retryableRefreshFailure = true;
    constructor(message?: string);
}

declare class TokenRefreshAbortError extends AxiosRetryerError {
    readonly stopRefreshRetries = true;
    constructor(message?: string);
}

declare class TokenRefreshFailedError extends AxiosRetryerError {
    constructor(message?: string);
}

/**
 * Raised when the TokenRefreshPlugin queue exceeds `maxQueuedRequests`.
 * Prevents unbounded memory growth (and a DoS surface) under sustained 401 conditions.
 */
declare class TokenRefreshQueueOverflowError extends AxiosRetryerError {
    readonly queueSize: number;
    constructor(queueSize: number);
}

/**
 * Creates a TokenRefreshPlugin instance.
 * Functional alternative to using the `new TokenRefreshPlugin()` constructor.
 *
 * @param refreshToken Function that performs the token refresh operation. Return `{ token: string }` to apply a new token, or resolve with no usable `token` (`null`/`undefined`/omitted) to skip that cycle without failure events (see plugin docs).
 * @param options Configuration options for the TokenRefreshPlugin
 * @returns A configured TokenRefreshPlugin instance
 *
 * @example
 * ```typescript
 * const tokenRefresher = createTokenRefreshPlugin(
 *   async (axiosInstance) => {
 *     const refreshToken = localStorage.getItem('refreshToken');
 *     if (!refreshToken) {
 *       throw new TokenRefreshAbortError('Refresh token not found');
 *     }
 *     const { data } = await axiosInstance.post('/auth/refresh', { refreshToken });
 *     return { token: data.accessToken };
 *   },
 *   {
 *     authHeaderName: 'Authorization',
 *     tokenPrefix: 'Bearer '
 *   }
 * );
 *
 * manager.use(tokenRefresher);
 * ```
 */
declare function createTokenRefreshPlugin(refreshToken: TokenRefreshHandler, options?: TokenRefreshPluginOptions): TokenRefreshPlugin;

export { MissingTokenRefreshHandlerError, TokenRefreshAbortError, TokenRefreshFailedError, TokenRefreshPlugin, TokenRefreshQueueOverflowError, TokenRefreshTimeoutError, createTokenRefreshPlugin };
export type { TokenRefreshHandler, TokenRefreshPluginEvents, TokenRefreshPluginOptions, TokenRefreshResult };