Exa Local Dev Loop

Overview

Set up a fast, reproducible local development workflow for Exa integrations. Covers project structure, mock responses for unit tests, integration test patterns, and hot-reload configuration.

Prerequisites

• exa-js installed and EXA_API_KEY configured
• Node.js 18+ with npm/pnpm
• vitest for testing (or jest)

Instructions

Step 1: Project Structure

my-exa-project/
├── src/
│   ├── exa/
│   │   ├── client.ts       # Singleton Exa client
│   │   ├── search.ts       # Search wrappers
│   │   └── types.ts        # Typed interfaces
│   └── index.ts
├── tests/
│   ├── exa.unit.test.ts    # Mock-based unit tests
│   └── exa.integration.test.ts  # Real API tests (needs key)
├── .env.local              # Local secrets (git-ignored)
├── .env.example            # Template for team
├── tsconfig.json
├── vitest.config.ts
└── package.json

Step 2: Package Setup

{
  "scripts": {
    "dev": "tsx watch src/index.ts",
    "test": "vitest",
    "test:unit": "vitest --testPathPattern=unit",
    "test:integration": "vitest --testPathPattern=integration",
    "build": "tsc"
  },
  "dependencies": {
    "exa-js": "^1.0.0"
  },
  "devDependencies": {
    "tsx": "^4.0.0",
    "vitest": "^2.0.0",
    "typescript": "^5.0.0"
  }
}

Step 3: Mock Exa for Unit Tests

// tests/exa.unit.test.ts
import { describe, it, expect, vi, beforeEach } from "vitest";

// Mock the exa-js module
vi.mock("exa-js", () => {
  return {
    default: vi.fn().mockImplementation(() => ({
      search: vi.fn().mockResolvedValue({
        results: [
          { url: "https://example.com/1", title: "Test Result 1", score: 0.95 },
          { url: "https://example.com/2", title: "Test Result 2", score: 0.87 },
        ],
      }),
      searchAndContents: vi.fn().mockResolvedValue({
        results: [
          {
            url: "https://example.com/1",
            title: "Test Result 1",
            score: 0.95,
            text: "This is the full text content of the page.",
            highlights: ["Key excerpt from the page"],
            summary: "A summary of the page content.",
          },
        ],
      }),
      findSimilar: vi.fn().mockResolvedValue({
        results: [
          { url: "https://similar.com/1", title: "Similar Page", score: 0.82 },
        ],
      }),
      getContents: vi.fn().mockResolvedValue({
        results: [
          { url: "https://example.com/1", title: "Page", text: "Content" },
        ],
      }),
    })),
  };
});

import Exa from "exa-js";

describe("Exa Search", () => {
  let exa: any;

  beforeEach(() => {
    exa = new Exa("test-key");
  });

  it("should return search results", async () => {
    const result = await exa.search("test query", { numResults: 5 });
    expect(result.results).toHaveLength(2);
    expect(result.results[0].score).toBeGreaterThan(0.9);
  });

  it("should return content with searchAndContents", async () => {
    const result = await exa.searchAndContents("test", { text: true });
    expect(result.results[0].text).toBeDefined();
    expect(result.results[0].highlights).toHaveLength(1);
  });
});

Step 4: Integration Tests (Real API)

// tests/exa.integration.test.ts
import { describe, it, expect } from "vitest";
import Exa from "exa-js";

// Skip if no API key available (CI without secrets)
const describeWithKey = process.env.EXA_API_KEY
  ? describe
  : describe.skip;

describeWithKey("Exa Integration", () => {
  const exa = new Exa(process.env.EXA_API_KEY!);

  it("should execute a basic search", async () => {
    const result = await exa.search("test connectivity", { numResults: 1 });
    expect(result.results.length).toBeGreaterThanOrEqual(1);
    expect(result.results[0].url).toMatch(/^https?:\/\//);
  }, 10000); // 10s timeout for API calls

  it("should return text content", async () => {
    const result = await exa.searchAndContents("TypeScript tutorial", {
      numResults: 1,
      text: { maxCharacters: 500 },
    });
    expect(result.results[0].text).toBeDefined();
    expect(result.results[0].text!.length).toBeGreaterThan(0);
  }, 15000);

  it("should find similar pages", async () => {
    const result = await exa.findSimilar("https://nodejs.org", {
      numResults: 3,
    });
    expect(result.results.length).toBeGreaterThanOrEqual(1);
  }, 10000);
});

Step 5: Environment Configuration

set -euo pipefail
# Create .env.example template (commit this)
cat > .env.example << 'EOF'
# Exa API — get key at https://dashboard.exa.ai
EXA_API_KEY=
EOF

# Create local env (git-ignored)
cp .env.example .env.local
echo "EXA_API_KEY=your-key-here" > .env.local

Error Handling

Error	Cause	Solution
Cannot find module 'exa-js'	Not installed	Run npm install exa-js
Test timeout	Slow API response	Increase vitest timeout to 15000ms
Mock not applied	Import order issue	Ensure vi.mock() is before imports
Integration test fails in CI	No API key secret	Add EXA_API_KEY to CI secrets or skip

Examples

Vitest Config for Exa Projects

// vitest.config.ts
import { defineConfig } from "vitest/config";

export default defineConfig({
  test: {
    globals: true,
    environment: "node",
    testTimeout: 15000,   // Exa API calls can take a few seconds
    setupFiles: ["dotenv/config"],
  },
});

Resources

• Vitest Documentation
• tsx Documentation
• exa-js on npm

Next Steps

See exa-sdk-patterns for production-ready code patterns.