apollo-sdk-patterns

# Apollo SDK Patterns

## Overview
Production-ready patterns for Apollo.io API integration with type safety, error handling, and retry logic.

## Prerequisites
- Completed `apollo-install-auth` setup
- Familiarity with async/await patterns
- Understanding of TypeScript generics

## Pattern 1: Type-Safe Client Singleton

```typescript
// src/lib/apollo/client.ts
import axios, { AxiosInstance, AxiosError } from 'axios';
import { z } from 'zod';

// Response schemas
const PersonSchema = z.object({
  id: z.string(),
  name: z.string(),
  first_name: z.string().optional(),
  last_name: z.string().optional(),
  title: z.string().optional(),
  email: z.string().email().optional(),
  linkedin_url: z.string().url().optional(),
  organization: z.object({
    id: z.string(),
    name: z.string(),
    domain: z.string().optional(),
  }).optional(),
});

const PeopleSearchResponseSchema = z.object({
  people: z.array(PersonSchema),
  pagination: z.object({
    page: z.number(),
    per_page: z.number(),
    total_entries: z.number(),
    total_pages: z.number(),
  }),
});

export type Person = z.infer<typeof PersonSchema>;
export type PeopleSearchResponse = z.infer<typeof PeopleSearchResponseSchema>;

class ApolloClient {
  private static instance: ApolloClient;
  private client: AxiosInstance;

  private constructor() {
    this.client = axios.create({
      baseURL: 'https://api.apollo.io/v1',
      timeout: 30000,
      headers: { 'Content-Type': 'application/json' },
      params: { api_key: process.env.APOLLO_API_KEY },
    });

    this.setupInterceptors();
  }

  static getInstance(): ApolloClient {
    if (!ApolloClient.instance) {
      ApolloClient.instance = new ApolloClient();
    }
    return ApolloClient.instance;
  }

  private setupInterceptors() {
    this.client.interceptors.response.use(
      (response) => response,
      this.handleError.bind(this)
    );
  }

  private handleError(error: AxiosError) {
    if (error.response?.status === 429) {
      throw ne