TypeScript Support

MentiQ Analytics SDK is built with TypeScript and provides comprehensive type definitions for all features. This guide covers all the types, interfaces, and type-safe patterns you’ll use.

Core Configuration

AnalyticsConfig

The main configuration interface for initializing the Analytics SDK:

interface AnalyticsConfig {
  // Required
  apiKey: string;                    // Your MentiQ API key
  projectId: string;                 // Your MentiQ project ID

  // Optional - Connection
  endpoint?: string;                 // Default: "https://api.mentiq.io"
  debug?: boolean;                   // Enable console logging (default: false)

  // Optional - User & Session
  userId?: string;                   // Set initial user ID
  sessionTimeout?: number;           // Session timeout in ms (default: 30 min)

  // Optional - Batching & Queuing
  batchSize?: number;                // Events per batch (default: 20)
  flushInterval?: number;            // Auto-flush interval in ms (default: 10s)
  maxQueueSize?: number;             // Max queued events (default: 1000)
  retryAttempts?: number;            // Failed request retries (default: 3)
  retryDelay?: number;               // Retry delay in ms (default: 1000)

  // Optional - Automatic Tracking
  enableAutoPageTracking?: boolean;       // Auto-track page views (default: true)
  enablePerformanceTracking?: boolean;    // Track performance metrics
  enableHeatmapTracking?: boolean;        // Track clicks and hovers
  enableSessionRecording?: boolean;       // Enable session replay
  enableErrorTracking?: boolean;          // Auto-track errors

  // Optional - A/B Testing
  enableABTesting?: boolean;              // Enable A/B testing
  abTestConfig?: ABTestConfig;            // A/B test configuration
}

Usage Example

import { Analytics, AnalyticsConfig } from "mentiq-sdk";

const config: AnalyticsConfig = {
  apiKey: "pk_live_1234567890",
  projectId: "proj_abc123",
  endpoint: "https://analytics.myapp.com",
  debug: process.env.NODE_ENV === "development",
  
  // Batching configuration
  batchSize: 25,
  flushInterval: 5000,
  maxQueueSize: 500,
  
  // Feature flags
  enableAutoPageTracking: true,
  enablePerformanceTracking: true,
  enableErrorTracking: true,
};

const analytics = new Analytics(config);

Event Types

EventProperties

Base type for all event properties:

interface EventProperties {
  [key: string]: string | number | boolean | null | undefined;
}

PageProperties

Properties for page view events:

interface PageProperties {
  title?: string;        // Page title
  url?: string;          // Full URL
  path?: string;         // URL path
  referrer?: string;     // Referrer URL
  search?: string;       // Query string
}

Example:

import { useAnalytics } from "mentiq-sdk";
import type { PageProperties } from "mentiq-sdk";

function MyComponent() {
  const { page } = useAnalytics();

  const trackPage = () => {
    const properties: PageProperties = {
      title: "Product Details",
      url: window.location.href,
      path: "/products/123",
      referrer: document.referrer,
    };
    page(properties);
  };
}

UserProperties

Properties for user identification:

interface UserProperties {
  subscription?: SubscriptionProperties;  // User subscription data
  [key: string]:                         // Any custom properties
    | string
    | number
    | boolean
    | null
    | undefined
    | SubscriptionProperties;
}

Example:

import type { UserProperties } from "mentiq-sdk";

const userTraits: UserProperties = {
  email: "[email protected]",
  name: "John Doe",
  plan: "premium",
  company: "Acme Inc",
  created_at: "2024-01-15",
};

analytics.identify("user_123", userTraits);

Subscription Tracking Types

SubscriptionProperties

Comprehensive subscription data structure:

interface SubscriptionProperties {
  // Status & Plan
  status:
    | "active"
    | "trialing"
    | "past_due"
    | "canceled"
    | "paused"
    | "incomplete"
    | "incomplete_expired"
    | "unpaid";
  plan_id?: string;
  plan_name?: string;
  plan_tier?: string;              // e.g., "free", "starter", "pro"

  // Pricing (in cents)
  mrr?: number;                    // Monthly Recurring Revenue
  arr?: number;                    // Annual Recurring Revenue
  ltv?: number;                    // Lifetime Value
  currency?: string;               // e.g., "usd", "eur"

  // Billing Cycle
  billing_interval?: "day" | "week" | "month" | "year";
  billing_cycle_anchor?: string;   // ISO date
  current_period_start?: string;   // ISO date
  current_period_end?: string;     // ISO date

  // Trial
  trial_start?: string;            // ISO date
  trial_end?: string;              // ISO date
  is_trial?: boolean;

  // Payment (PCI-safe)
  payment_method_type?: string;    // e.g., "card", "bank_account"
  payment_method_last4?: string;   // Last 4 digits only
  payment_method_brand?: string;   // e.g., "visa", "mastercard"

  // Cancellation
  cancel_at_period_end?: boolean;
  canceled_at?: string;            // ISO date
  cancellation_reason?: string;

  // Provider Info
  provider?: "stripe" | "paddle" | "chargebee" | "manual" | string;
  provider_customer_id?: string;
  provider_subscription_id?: string;

  // Metadata
  created_at?: string;             // ISO date
  updated_at?: string;             // ISO date

  // Custom fields
  [key: string]: string | number | boolean | null | undefined;
}

Example:

import type { SubscriptionProperties } from "mentiq-sdk";

const subscription: SubscriptionProperties = {
  status: "active",
  plan_id: "price_premium_monthly",
  plan_name: "Premium Plan",
  plan_tier: "premium",
  mrr: 2900,  // $29.00 in cents
  currency: "usd",
  billing_interval: "month",
  current_period_start: "2024-01-01T00:00:00Z",
  current_period_end: "2024-02-01T00:00:00Z",
  provider: "stripe",
  provider_subscription_id: "sub_1234567890",
  payment_method_type: "card",
  payment_method_last4: "4242",
  payment_method_brand: "visa",
};

analytics.identify("user_123", { subscription });

PaymentEventProperties

Properties for payment events:

interface PaymentEventProperties extends EventProperties {
  amount?: number;                              // Payment amount
  currency?: string;                            // Currency code
  payment_status?: "succeeded" | "failed" | "pending" | "refunded";
  failure_reason?: string;                      // Reason for failure
  invoice_id?: string;                          // Invoice identifier
  charge_id?: string;                           // Charge identifier
}

Example:

import type { PaymentEventProperties } from "mentiq-sdk";

const paymentEvent: PaymentEventProperties = {
  amount: 2900,
  currency: "usd",
  payment_status: "succeeded",
  invoice_id: "inv_123",
  charge_id: "ch_456",
};

analytics.trackPaymentSucceeded(paymentEvent);

ChurnRiskMetrics

Churn risk analysis result:

interface ChurnRiskMetrics {
  risk_score: number;                          // 0-100
  risk_category: "low" | "medium" | "high" | "critical";
  factors: {
    engagement_score?: number;
    days_since_last_active?: number;
    feature_adoption_rate?: number;
    support_tickets?: number;
    negative_feedback_count?: number;
    payment_failures?: number;
  };
  predicted_churn_date?: string;               // ISO date
  intervention_recommended?: boolean;
}

Example:

const churnRisk = analytics.calculateChurnRisk();

if (churnRisk.risk_category === "high" || churnRisk.risk_category === "critical") {
  // Trigger intervention campaign
  triggerRetentionCampaign(churnRisk);
}

Session Types

SessionData

Real-time session tracking data:

interface SessionData {
  sessionId?: string;              // Session identifier
  startTime: number;               // Session start timestamp
  endTime?: number;                // Session end timestamp
  duration?: number;               // Duration in milliseconds
  pageViews: number;               // Number of page views
  clicks: number;                  // Number of clicks
  scrollDepth: number;             // Current scroll depth %
  maxScrollDepth: number;          // Maximum scroll depth %
  isActive: boolean;               // Is session currently active
  events: string[];                // List of event names
  scrollEvents?: number;           // Number of scroll events
  clickEvents?: number;            // Number of click events
  pageChanges?: number;            // Number of page changes
  engagementScore?: number;        // Engagement score (0-100)
  bounceLikelihood?: number;       // Bounce likelihood % (0-100)
  channel?: string;                // Traffic source channel
}

Example:

import { useSessionTracking } from "mentiq-sdk";
import type { SessionData } from "mentiq-sdk";

function SessionMonitor() {
  const { sessionData } = useSessionTracking();

  const renderEngagement = (data: SessionData) => {
    const score = data.engagementScore || 0;
    return (
      <div>
        <p>Engagement: {score.toFixed(0)}%</p>
        <p>Page Views: {data.pageViews}</p>
        <p>Scroll Depth: {data.maxScrollDepth}%</p>
      </div>
    );
  };

  return sessionData ? renderEngagement(sessionData) : null;
}

Performance Types

PerformanceData

Core Web Vitals and performance metrics:

interface PerformanceData {
  loadTime?: number;                    // Total page load time
  domReady?: number;                    // DOM ready time
  firstPaint?: number;                  // First Paint (FP)
  firstContentfulPaint?: number;        // First Contentful Paint (FCP)
  largestContentfulPaint?: number;      // Largest Contentful Paint (LCP)
  firstInputDelay?: number;             // First Input Delay (FID)
  cumulativeLayoutShift?: number;       // Cumulative Layout Shift (CLS)
  timeToInteractive?: number;           // Time to Interactive (TTI)
}

Example:

import type { PerformanceData } from "mentiq-sdk";

const perfData: PerformanceData = {
  loadTime: 1250,
  firstContentfulPaint: 800,
  largestContentfulPaint: 1200,
  firstInputDelay: 50,
  cumulativeLayoutShift: 0.05,
};

analytics.trackPerformance(perfData);

Error Tracking Types

ErrorData

Error information structure:

interface ErrorData {
  message: string;                     // Error message
  stack?: string;                      // Stack trace
  filename?: string;                   // File where error occurred
  lineno?: number;                     // Line number
  colno?: number;                      // Column number
  type: "javascript"                   // Error type
      | "unhandledrejection"
      | "network"
      | "custom";
}

Example:

import { useAnalytics } from "mentiq-sdk";
import type { ErrorData } from "mentiq-sdk";

function MyComponent() {
  const { trackCustomError } = useAnalytics();

  const handleError = (error: Error) => {
    trackCustomError(error, {
      component: "MyComponent",
      action: "data_fetch",
      severity: "high",
    });
  };
}

Heatmap Types

HeatmapData

User interaction data for heatmaps:

interface HeatmapData {
  x: number;                          // X coordinate
  y: number;                          // Y coordinate
  element?: string;                   // Element tag name
  selector?: string;                  // CSS selector
  action: "click" | "move" | "scroll"; // Interaction type
  viewport: {
    width: number;                    // Viewport width
    height: number;                   // Viewport height
  };
}

Analytics Instance Type

AnalyticsInstance

Complete interface for the Analytics class:

interface AnalyticsInstance {
  // Core tracking
  track: (event: string, properties?: EventProperties) => void;
  page: (properties?: PageProperties) => void;
  identify: (
    userId: string,
    traits?: UserProperties & { email?: string; subscription?: SubscriptionProperties }
  ) => void;
  alias: (newId: string, previousId?: string) => void;
  reset: () => void;
  flush: () => Promise<void>;

  // User & Session
  setUserId: (userId: string) => void;
  getUserId: () => string | null;
  getAnonymousId: () => string;
  getSessionId: () => string;
  getSessionData: () => SessionData;
  getActiveSession: () => SessionData;
  calculateEngagementScore: () => number;

  // Queue management
  getQueueSize: () => number;
  clearQueue: () => void;

  // Error tracking
  trackCustomError: (error: string | Error, properties?: EventProperties) => void;

  // Performance
  trackPerformance: (performanceData: PerformanceData) => void;

  // Feature tracking
  trackFeatureUsage: (featureName: string, properties?: EventProperties) => void;

  // Funnel tracking
  trackFunnelStep: (
    funnelName: string,
    stepName: string,
    stepIndex: number,
    properties?: EventProperties
  ) => void;
  completeFunnel: (funnelName: string, properties?: EventProperties) => void;
  startFunnel: (funnelName: string, properties?: EventProperties) => void;
  advanceFunnel: (
    funnelName: string,
    stepName: string,
    properties?: EventProperties
  ) => void;
  abandonFunnel: (
    funnelName: string,
    reason?: string,
    properties?: EventProperties
  ) => void;
  getFunnelState: (funnelName: string) => FunnelState | undefined;

  // Session recording
  startRecording: () => void;
  stopRecording: () => void;
  pauseRecording: () => void;
  resumeRecording: () => void;
  isRecordingActive: () => boolean;

  // Subscription tracking
  trackSubscription: (
    eventName: string,
    properties?: SubscriptionProperties & EventProperties
  ) => void;
  trackSubscriptionStarted: (properties: SubscriptionProperties) => void;
  trackSubscriptionUpgraded: (
    properties: SubscriptionProperties & { previous_plan?: string }
  ) => void;
  trackSubscriptionDowngraded: (
    properties: SubscriptionProperties & { previous_plan?: string }
  ) => void;
  trackSubscriptionCanceled: (
    properties: SubscriptionProperties & { cancellation_reason?: string }
  ) => void;
  trackSubscriptionPaused: (properties: SubscriptionProperties) => void;
  trackSubscriptionReactivated: (properties: SubscriptionProperties) => void;
  trackTrialStarted: (properties: SubscriptionProperties) => void;
  trackTrialConverted: (properties: SubscriptionProperties) => void;
  trackTrialExpired: (properties: SubscriptionProperties) => void;
  trackPaymentFailed: (properties: PaymentEventProperties) => void;
  trackPaymentSucceeded: (properties: PaymentEventProperties) => void;

  // Churn analysis
  calculateChurnRisk: () => ChurnRiskMetrics;
  getSubscriptionData: () => SubscriptionProperties | null;

  // Configuration
  config: AnalyticsConfig;
}

A/B Testing Types

Experiment

interface Experiment {
  id: string;
  name: string;
  description?: string;
  key: string;
  status: "DRAFT" | "RUNNING" | "PAUSED" | "COMPLETED" | "ARCHIVED";
  trafficSplit: number;
  startDate?: string;
  endDate?: string;
  createdAt: string;
  updatedAt: string;
  variants: Variant[];
}

Variant

interface Variant {
  id: string;
  name: string;
  key: string;
  description?: string;
  isControl: boolean;
  trafficSplit: number;
  createdAt: string;
  updatedAt: string;
}

ExperimentAssignment

interface ExperimentAssignment {
  experimentId: string;
  variantId: string;
  variantKey: string;
  variantName: string;
  isControl: boolean;
  assignedAt: string;
  experiment?: Experiment;
}

Type Guards

Create type-safe helpers for runtime type checking:

import type { SubscriptionProperties, PaymentEventProperties } from "mentiq-sdk";

function isActiveSubscription(
  sub: SubscriptionProperties
): sub is SubscriptionProperties & { status: "active" } {
  return sub.status === "active";
}

function isPaymentSuccess(
  payment: PaymentEventProperties
): payment is PaymentEventProperties & { payment_status: "succeeded" } {
  return payment.payment_status === "succeeded";
}

// Usage
const subscription = analytics.getSubscriptionData();
if (subscription && isActiveSubscription(subscription)) {
  // TypeScript knows status is "active" here
  console.log("User has active subscription");
}

Generic Event Typing

Create strongly-typed custom events:

import type { EventProperties } from "mentiq-sdk";

interface ProductViewEvent extends EventProperties {
  product_id: string;
  product_name: string;
  category: string;
  price: number;
  currency: string;
}

interface AddToCartEvent extends EventProperties {
  product_id: string;
  quantity: number;
  price: number;
}

// Type-safe tracking
function trackProductView(event: ProductViewEvent) {
  analytics.track("product_viewed", event);
}

trackProductView({
  product_id: "prod_123",
  product_name: "Premium Widget",
  category: "widgets",
  price: 29.99,
  currency: "usd",
});

Utility Types

Useful type utilities for common patterns:

import type { EventProperties, AnalyticsConfig } from "mentiq-sdk";

// Partial config for updates
type PartialConfig = Partial<AnalyticsConfig>;

// Required event properties
type RequiredEventProps<T extends EventProperties> = {
  [K in keyof T]-?: T[K];
};

// Event with metadata
type EventWithMetadata<T extends EventProperties = EventProperties> = T & {
  _timestamp: number;
  _userId?: string;
  _sessionId: string;
};

Get Started

Core Concepts

React Integration

Features

Guides

Examples

TypeScript Support

TypeScript Support

Core Configuration

AnalyticsConfig

Usage Example

Event Types

EventProperties

PageProperties

UserProperties

Subscription Tracking Types

SubscriptionProperties

PaymentEventProperties

ChurnRiskMetrics

Session Types

SessionData

Performance Types

PerformanceData

Error Tracking Types

ErrorData

Heatmap Types

HeatmapData

Analytics Instance Type

AnalyticsInstance

A/B Testing Types

Experiment

Variant

ExperimentAssignment

Type Guards

Generic Event Typing

Utility Types

Next Steps

Next.js Integration

Event Batching

Build docs developers (and LLMs) love

Get Started

Core Concepts

React Integration

Features

Guides

Examples

​TypeScript Support

​Core Configuration

​AnalyticsConfig

​Usage Example

​Event Types

​EventProperties

​PageProperties

​UserProperties

​Subscription Tracking Types

​SubscriptionProperties

​PaymentEventProperties

​ChurnRiskMetrics

​Session Types

​SessionData

​Performance Types

​PerformanceData

​Error Tracking Types

​ErrorData

​Heatmap Types

​HeatmapData

​Analytics Instance Type

​AnalyticsInstance

​A/B Testing Types

​Experiment

​Variant

​ExperimentAssignment

​Type Guards

​Generic Event Typing

​Utility Types

​Next Steps

Next.js Integration

Event Batching

Build docs developers (and LLMs) love

TypeScript Support

Core Configuration

AnalyticsConfig

Usage Example

Event Types

EventProperties

PageProperties

UserProperties

Subscription Tracking Types

SubscriptionProperties

PaymentEventProperties

ChurnRiskMetrics

Session Types

SessionData

Performance Types

PerformanceData

Error Tracking Types

ErrorData

Heatmap Types

HeatmapData

Analytics Instance Type

AnalyticsInstance

A/B Testing Types

Experiment

Variant

ExperimentAssignment

Type Guards

Generic Event Typing

Utility Types

Next Steps