Implement CoinGecko API Client with Comprehensive Data Fetching

.gitignore

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+node_modules/
+dist/
+.env
+*.log
+.DS_Store
+__pycache__
+.vscode/
+*.swp
+.idea/
+coverage/
+.nyc_output/

package.json

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+{
+  "name": "coin-gekko-api",
+  "version": "1.0.0",
+  "description": "Coin Gekko API for cryptocurrency trading",
+  "main": "dist/index.js",
+  "scripts": {
+    "build": "tsc",
+    "test": "vitest",
+    "start": "node dist/index.js"
+  },
+  "keywords": ["cryptocurrency", "trading", "api"],
+  "author": "",
+  "license": "ISC",
+  "devDependencies": {
+    "@types/node": "^16.11.10",
+    "typescript": "^4.5.4",
+    "vitest": "^0.25.3"
+  },
+  "dependencies": {
+    "axios": "^0.24.0"
+  }
+}

src/index.test.ts

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+import { describe, it, expect } from 'vitest';
+import { CoinGekkoApi } from './index';
+
+describe('CoinGekkoApi', () => {
+  const api = new CoinGekkoApi();
+
+  it('should fetch coin data for bitcoin', async () => {
+    const result = await api.fetchCoinData('bitcoin');
+
+    expect(result.success).toBe(true);
+    expect(result.data).toHaveProperty('id', 'bitcoin');
+    expect(result.data).toHaveProperty('symbol');
+    expect(result.data).toHaveProperty('name');
+    expect(result.data.price).toBeGreaterThan(0);
+  });
+
+  it('should list top coins', async () => {
+    const result = await api.listCoins(10);
+
+    expect(result.success).toBe(true);
+    expect(result.data.length).toBe(10);
+
+    result.data.forEach(coin => {
+      expect(coin).toHaveProperty('id');
+      expect(coin).toHaveProperty('symbol');
+      expect(coin).toHaveProperty('name');
+      expect(coin.price).toBeGreaterThan(0);
+    });
+  });
+
+  it('should handle invalid coin id', async () => {
+    const result = await api.fetchCoinData('non_existent_coin');
+
+    expect(result.success).toBe(false);
+    expect(result.error).toBeTruthy();
+  });
+});

src/index.ts

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+import axios from 'axios';
+import { CoinData, CoinGekkoApiOptions, FetchResult } from './types';
+
+export class CoinGekkoApi {
+  private baseUrl: string;
+  private apiKey?: string;
+
+  constructor(options: CoinGekkoApiOptions = {}) {
+    this.baseUrl = options.baseUrl || 'https://api.coingecko.com/api/v3';
+    this.apiKey = options.apiKey;
+  }
+
+  async fetchCoinData(coinId: string): Promise<FetchResult<CoinData>> {
+    try {
+      const response = await axios.get(`${this.baseUrl}/coins/${coinId}`);
+
+      if (response.status !== 200) {
+        return {
+          success: false,
+          data: {} as CoinData,
+          error: 'Failed to fetch coin data'
+        };
+      }
+
+      const data = response.data;
+      return {
+        success: true,
+        data: {
+          id: data.id,
+          symbol: data.symbol,
+          name: data.name,
+          price: data.market_data.current_price.usd,
+          marketCap: data.market_data.market_cap.usd,
+          volume24h: data.market_data.total_volume.usd
+        }
+      };
+    } catch (error) {
+      return {
+        success: false,
+        data: {} as CoinData,
+        error: error instanceof Error ? error.message : 'Unknown error'
+      };
+    }
+  }
+
+  async listCoins(limit: number = 100): Promise<FetchResult<CoinData[]>> {
+    try {
+      const response = await axios.get(`${this.baseUrl}/coins/markets`, {
+        params: {
+          vs_currency: 'usd',
+          order: 'market_cap_desc',
+          per_page: limit,
+          page: 1
+        }
+      });
+
+      if (response.status !== 200) {
+        return {
+          success: false,
+          data: [],
+          error: 'Failed to fetch coin list'
+        };
+      }
+
+      const coins: CoinData[] = response.data.map((coin: any) => ({
+        id: coin.id,
+        symbol: coin.symbol,
+        name: coin.name,
+        price: coin.current_price,
+        marketCap: coin.market_cap,
+        volume24h: coin.total_volume
+      }));
+
+      return {
+        success: true,
+        data: coins
+      };
+    } catch (error) {
+      return {
+        success: false,
+        data: [],
+        error: error instanceof Error ? error.message : 'Unknown error'
+      };
+    }
+  }
+}

src/types.ts

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+export interface CoinData {
+  id: string;
+  symbol: string;
+  name: string;
+  price: number;
+  marketCap: number;
+  volume24h: number;
+}
+
+export interface CoinGekkoApiOptions {
+  apiKey?: string;
+  baseUrl?: string;
+}
+
+export interface FetchResult<T> {
+  data: T;
+  success: boolean;
+  error?: string;
+}

tsconfig.json

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+{
+  "compilerOptions": {
+    "target": "es2020",
+    "module": "commonjs",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "outDir": "./dist",
+    "rootDir": "./src"
+  },
+  "include": ["src/**/*"],
+  "exclude": ["node_modules", "**/*.spec.ts"]
+}