Best Practices

Follow these best practices to get the most out of ByteKit while maintaining clean, performant, and maintainable code.

Error Handling

1. Always Catch Errors

Never let API errors bubble up unhandled:

import { ApiError } from 'bytekit';

// Good: Handle errors explicitly
try {
  const user = await client.get<User>('/users/1');
  return user;
} catch (err) {
  if (err instanceof ApiError) {
    // Handle API errors
    if (err.status === 404) {
      return null;  // User not found
    } else if (err.status === 401) {
      redirectToLogin();
    } else {
      showErrorToast(err.message);
    }
  }
  // Re-throw unknown errors
  throw err;
}

// Bad: Let errors propagate
const user = await client.get<User>('/users/1');

2. Provide User-Friendly Messages

Don’t show raw error messages to users:

// Good: User-friendly messages
try {
  await client.post('/users', userData);
  toast.success('User created successfully!');
} catch (err) {
  if (err instanceof ApiError) {
    if (err.status === 400) {
      toast.error('Please check your input and try again.');
    } else if (err.status === 409) {
      toast.error('A user with this email already exists.');
    } else {
      toast.error('Failed to create user. Please try again.');
    }
  }
}

// Bad: Raw error messages
try {
  await client.post('/users', userData);
} catch (err) {
  alert(err.message);  // "Request failed with status 400"
}

3. Log Errors for Debugging

Always log errors with context:

import { createLogger, ApiError } from 'bytekit';

const logger = createLogger({ namespace: 'app' });

try {
  const result = await client.post('/orders', orderData);
} catch (err) {
  if (err instanceof ApiError) {
    // Log full error details
    logger.error('Order creation failed', {
      status: err.status,
      statusText: err.statusText,
      body: err.body,
      orderData
    }, err);
    
    // Show user-friendly message
    toast.error('Failed to create order');
  }
}

4. Handle Network Errors

Distinguish between different error types:

try {
  const data = await client.get('/data');
} catch (err) {
  if (err instanceof ApiError) {
    if (err.isTimeout) {
      toast.error('Request timed out. Please check your connection.');
    } else if (err.status >= 500) {
      toast.error('Server error. Please try again later.');
    } else if (err.status === 401) {
      toast.error('Please sign in to continue.');
      redirectToLogin();
    } else {
      toast.error(err.message);
    }
  } else {
    // Network error or other unexpected error
    toast.error('Network error. Please check your connection.');
  }
}

Performance Optimization

1. Use Appropriate Cache Times

Set cache times based on data volatility:

const queryClient = createQueryClient(apiClient, {
  defaultStaleTime: 0,
  defaultCacheTime: 300000  // 5 minutes
});

// Frequently changing: short stale time
const livePrice = await queryClient.query({
  queryKey: ['price', symbol],
  path: `/stocks/${symbol}/price`,
  staleTime: 5000  // 5 seconds
});

// Rarely changing: long stale time
const config = await queryClient.query({
  queryKey: ['config'],
  path: '/config',
  staleTime: 3600000  // 1 hour
});

// Static data: infinite stale time
const countries = await queryClient.query({
  queryKey: ['countries'],
  path: '/countries',
  staleTime: Infinity
});

2. Enable Request Deduplication

Prevent duplicate requests:

const queryClient = createQueryClient(apiClient, {
  enableDeduplication: true
});

// These will only make ONE request
const [result1, result2, result3] = await Promise.all([
  queryClient.query({ queryKey: ['data'], path: '/data' }),
  queryClient.query({ queryKey: ['data'], path: '/data' }),
  queryClient.query({ queryKey: ['data'], path: '/data' })
]);

3. Use Circuit Breakers

Prevent cascading failures:

const client = createApiClient({
  baseUrl: 'https://api.example.com',
  circuitBreaker: {
    threshold: 5,        // Open after 5 failures
    timeout: 60000,      // Stay open for 60s
    resetTimeout: 30000  // Try to close after 30s
  }
});

4. Set Appropriate Timeouts

Don’t let requests hang indefinitely:

// Short timeout for health checks
const health = await client.get('/health', {
  timeoutMs: 5000
});

// Longer timeout for file uploads
const upload = await client.post('/upload', formData, {
  timeoutMs: 60000  // 1 minute
});

5. Batch Requests When Possible

// Good: Single request for multiple items
const users = await client.get('/users', {
  searchParams: { ids: [1, 2, 3, 4, 5] }
});

// Bad: Multiple requests
const users = await Promise.all([
  client.get('/users/1'),
  client.get('/users/2'),
  client.get('/users/3'),
  client.get('/users/4'),
  client.get('/users/5')
]);

Tree-Shaking

ByteKit is designed for optimal tree-shaking. Follow these practices to minimize bundle size:

1. Import Only What You Need

// Good: Named imports
import { createApiClient, createLogger } from 'bytekit';

// Bad: Import everything
import * as ByteKit from 'bytekit';
const client = ByteKit.createApiClient(...);

2. Use Specific Import Paths

For even better tree-shaking, import from specific paths:

// Even better: Direct path imports
import { createApiClient } from 'bytekit/core';
import { createLogger } from 'bytekit/core';
import { StringUtils } from 'bytekit/helpers';

3. Avoid Importing Unused Utilities

// Good: Only import what you use
import { createApiClient } from 'bytekit';

// Bad: Import unused utilities
import {
  createApiClient,
  createLogger,      // Not used
  Profiler,          // Not used
  StringUtils,       // Not used
  DateUtils          // Not used
} from 'bytekit';

4. Check Bundle Size

Use bundle analyzers to verify tree-shaking:

# Webpack Bundle Analyzer
npm install --save-dev webpack-bundle-analyzer

# Rollup Plugin Visualizer
npm install --save-dev rollup-plugin-visualizer

# Vite Bundle Analyzer
npm install --save-dev rollup-plugin-visualizer

Testing

1. Mock API Client in Tests

import { vi, describe, it, expect } from 'vitest';
import type { ApiClient } from 'bytekit';

// Create mock client
const mockClient = {
  get: vi.fn(),
  post: vi.fn(),
  put: vi.fn(),
  delete: vi.fn()
} as unknown as ApiClient;

// Test
describe('UserService', () => {
  it('should fetch user', async () => {
    mockClient.get.mockResolvedValue({
      id: 1,
      name: 'John'
    });

    const service = new UserService(mockClient);
    const user = await service.getUser('1');

    expect(mockClient.get).toHaveBeenCalledWith('/users/1');
    expect(user.name).toBe('John');
  });
});

2. Test Error Handling

import { ApiError } from 'bytekit';

it('should handle 404 errors', async () => {
  mockClient.get.mockRejectedValue(
    new ApiError(404, 'Not Found', 'User not found')
  );

  const service = new UserService(mockClient);
  const user = await service.getUser('999');

  expect(user).toBeNull();
});

3. Use MSW for Integration Tests

import { setupServer } from 'msw/node';
import { rest } from 'msw';
import { createApiClient } from 'bytekit';

const server = setupServer(
  rest.get('https://api.example.com/users/:id', (req, res, ctx) => {
    return res(
      ctx.json({
        id: req.params.id,
        name: 'John Doe'
      })
    );
  })
);

beforeAll(() => server.listen());
afterEach(() => server.resetHandlers());
afterAll(() => server.close());

it('should fetch user from API', async () => {
  const client = createApiClient({
    baseUrl: 'https://api.example.com'
  });

  const user = await client.get('/users/1');
  expect(user.name).toBe('John Doe');
});

4. Test Retry Logic

it('should retry on failure', async () => {
  let attempts = 0;
  
  const server = setupServer(
    rest.get('https://api.example.com/data', (req, res, ctx) => {
      attempts++;
      if (attempts < 3) {
        return res(ctx.status(500));
      }
      return res(ctx.json({ success: true }));
    })
  );

  const client = createApiClient({
    baseUrl: 'https://api.example.com',
    retryPolicy: { maxRetries: 3 }
  });

  const result = await client.get('/data');
  
  expect(attempts).toBe(3);
  expect(result.success).toBe(true);
});

Code Organization

1. Create Dedicated API Services

// services/UserService.ts
import type { ApiClient } from 'bytekit';

export class UserService {
  constructor(private client: ApiClient) {}

  async getUser(id: string) {
    return this.client.get<User>(`/users/${id}`);
  }

  async updateUser(id: string, data: Partial<User>) {
    return this.client.put<User>(`/users/${id}`, data);
  }

  async deleteUser(id: string) {
    return this.client.delete(`/users/${id}`);
  }
}

// Usage
const userService = new UserService(apiClient);
const user = await userService.getUser('1');

2. Define TypeScript Interfaces

// types/api.ts
export interface User {
  id: number;
  name: string;
  email: string;
  role: 'admin' | 'user';
  createdAt: string;
}

export interface Post {
  id: number;
  title: string;
  content: string;
  authorId: number;
  author?: User;
}

export interface PaginatedResponse<T> {
  data: T[];
  total: number;
  page: number;
  pageSize: number;
}

3. Use Environment Variables

// lib/api.ts
import { createApiClient } from 'bytekit';

export const apiClient = createApiClient({
  baseUrl: process.env.NEXT_PUBLIC_API_URL || 'http://localhost:3000',
  defaultHeaders: {
    'Authorization': `Bearer ${process.env.API_TOKEN}`
  },
  timeoutMs: Number(process.env.API_TIMEOUT) || 15000
});

4. Centralize Configuration

// config/api.ts
import { createApiClient, createLogger } from 'bytekit';

const logger = createLogger({
  namespace: 'api',
  level: process.env.NODE_ENV === 'production' ? 'error' : 'debug'
});

export const apiClient = createApiClient({
  baseUrl: process.env.API_URL,
  logger,
  retryPolicy: {
    maxRetries: 3,
    initialDelayMs: 1000
  },
  circuitBreaker: {
    threshold: 5,
    timeout: 60000
  }
});

Security

1. Never Log Sensitive Data

// Good: Redact sensitive data
logger.info('User login', {
  userId: user.id,
  email: user.email
  // Don't log: password, tokens, credit cards
});

// Bad: Logging everything
logger.info('User login', user);  // May contain password

2. Use HTTPS in Production

const client = createApiClient({
  baseUrl: process.env.NODE_ENV === 'production'
    ? 'https://api.example.com'
    : 'http://localhost:3000'
});

3. Validate API Responses

const user = await client.get<User>('/users/1', {
  validateResponse: {
    id: { type: 'number', required: true },
    email: { type: 'string', required: true },
    role: { type: 'string', required: true }
  }
});

4. Set Appropriate CORS Headers

const client = createApiClient({
  baseUrl: 'https://api.example.com',
  defaultHeaders: {
    'Origin': window.location.origin
  }
});

Monitoring

1. Track API Performance

import { Profiler, createLogger } from 'bytekit';

const logger = createLogger({ namespace: 'perf' });
const profiler = new Profiler('api');

profiler.start('fetch-user');
const user = await client.get('/users/1');
profiler.end('fetch-user');

const timings = profiler.summary();
if (timings['fetch-user'] > 1000) {
  logger.warn('Slow API response', { timings });
}

2. Monitor Error Rates

const queryClient = createQueryClient(apiClient, {
  globalCallbacks: {
    onError: (error, context) => {
      // Send to error tracking service
      Sentry.captureException(error, {
        tags: {
          url: context.url,
          method: context.method
        }
      });
    }
  }
});

3. Use Structured Logging

const logger = createLogger({
  namespace: 'api',
  transports: [
    async (entry) => {
      // Send to logging service
      await fetch('https://logs.example.com/ingest', {
        method: 'POST',
        body: JSON.stringify({
          level: entry.level,
          message: entry.message,
          context: entry.context,
          timestamp: entry.timestamp
        })
      });
    }
  ]
});

Getting Started

Core Concepts

Guides

CLI Tool

Documentation Index

​Best Practices

​Error Handling

​1. Always Catch Errors

​2. Provide User-Friendly Messages

​3. Log Errors for Debugging

​4. Handle Network Errors

​Performance Optimization

​1. Use Appropriate Cache Times

​2. Enable Request Deduplication

​3. Use Circuit Breakers

​4. Set Appropriate Timeouts

​5. Batch Requests When Possible

​Tree-Shaking

​1. Import Only What You Need

​2. Use Specific Import Paths

​3. Avoid Importing Unused Utilities

​4. Check Bundle Size

​Testing

​1. Mock API Client in Tests

​2. Test Error Handling

​3. Use MSW for Integration Tests

​4. Test Retry Logic

​Code Organization

​1. Create Dedicated API Services

​2. Define TypeScript Interfaces

​3. Use Environment Variables

​4. Centralize Configuration

​Security

​1. Never Log Sensitive Data

​2. Use HTTPS in Production

​3. Validate API Responses

​4. Set Appropriate CORS Headers

​Monitoring

​1. Track API Performance

​2. Monitor Error Rates

​3. Use Structured Logging

​Related

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