jest.config.js

const nextJest = require('next/jest')

const createJestConfig = nextJest({
  // Provide the path to your Next.js app to load next.config.js and .env files
  dir: './',
})

// Add any custom config to be passed to Jest
const customJestConfig = {
  setupFilesAfterEnv: ['<rootDir>/jest.setup.js'],
  testEnvironment: 'jsdom',
  moduleNameMapper: {
    '^@/(.*)$': '<rootDir>/src/$1',
    '^src/(.*)$': '<rootDir>/src/$1',
  },
  testPathIgnorePatterns: ['<rootDir>/.next/', '<rootDir>/node_modules/'],
  transformIgnorePatterns: ['node_modules/(?!(@react-chess|chess.ts)/)'],
  transform: {
    '^.+\\.(js|jsx|ts|tsx)$': ['babel-jest', { presets: ['next/babel'] }],
  },
  moduleFileExtensions: ['ts', 'tsx', 'js', 'jsx'],
  collectCoverageFrom: [
    'src/**/*.{ts,tsx}',
    '!src/**/*.d.ts',
    '!src/pages/**',
    '!src/types/**',
  ],
  coverageReporters: ['text', 'lcov', 'html'],
  testMatch: [
    '<rootDir>/__tests__/**/*.{ts,tsx}',
    '<rootDir>/src/**/*.{test,spec}.{ts,tsx}',
  ],
}

// createJestConfig is exported this way to ensure that next/jest can load the Next.js config which is async
module.exports = createJestConfig(customJestConfig)