jest.config.ts

import type { Config } from "jest";
import nextJest from "next/jest.js";

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

// Add any custom config to be passed to Jest
const config: Config = {
  collectCoverage: false,
  // on node 14.x coverage provider v8 offers good speed and more or less good report
  coverageProvider: "v8",
  // collectCoverageFrom: [
  //   "**/*.{js,jsx,ts,tsx}",
  //   "!**/*.d.ts",
  //   "!**/node_modules/**",
  //   "!<rootDir>/out/**",
  //   "!<rootDir>/.next/**",
  //   "!<rootDir>/*.config.js",
  //   "!<rootDir>/coverage/**",
  // ],
  moduleNameMapper: {
    // Handle CSS imports (with CSS modules)
    // https://jestjs.io/docs/webpack#mocking-css-modules
    "^.+\\.module\\.(css|sass|scss)$": "identity-obj-proxy",

    // Handle CSS imports (without CSS modules)
    "^.+\\.(css|sass|scss)$": "<rootDir>/__mocks__/styleMock.js",

    // Handle image imports
    // https://jestjs.io/docs/webpack#handling-static-assets
    "^.+\\.(png|jpg|jpeg|gif|webp|avif|ico|bmp|svg)$": `<rootDir>/__mocks__/fileMock.js`,

    // Handle module aliases
    "^@/components/(.*)$": "<rootDir>/components/$1",
    "^~/(.*)$": "<rootDir>/src/$1",

    // Handle @next/font
    "@next/font/(.*)": `<rootDir>/__mocks__/nextFontMock.js`,
    // Handle next/font
    "next/font/(.*)": `<rootDir>/__mocks__/nextFontMock.js`,
    // Disable server-only
    "server-only": `<rootDir>/__mocks__/empty.js`,
  },
  // Add more setup options before each test is run
  // setupFilesAfterEnv: ['<rootDir>/jest.setup.js'],
  testPathIgnorePatterns: ["<rootDir>/node_modules/", "<rootDir>/.next/"],
  testEnvironment: "jsdom",
  transform: {
    // Use babel-jest to transpile tests with the next/babel preset
    // https://jestjs.io/docs/configuration#transform-objectstring-pathtotransformer--pathtotransformer-object
    "^.+\\.(js|jsx|ts|tsx)$": ["babel-jest", { presets: ["next/babel"] }],
  },
  transformIgnorePatterns: [
    "/node_modules/",
    "^.+\\.module\\.(css|sass|scss)$",
  ],
};

// createJestConfig is exported this way to ensure that next/jest can load the Next.js config which is async
export default createJestConfig(config);