jest.config.js

/**
 * For a detailed explanation regarding each configuration property, visit:
 * https://jestjs.io/docs/configuration
 */

const nextJest = require("next/jest");

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

/** @type {import('jest').Config} */
const config = {
  testPathIgnorePatterns: ['/node_modules/', 'e2e'],

  // Automatically clear mock calls, instances, contexts and results before every test
  clearMocks: true,

  // Indicates whether the coverage information should be collected while executing the test
  collectCoverage: true,

  // The directory where Jest should output its coverage files
  coverageDirectory: "coverage",

  // Indicates which provider should be used to instrument code for coverage
  coverageProvider: "v8",

  // The test environment that will be used for testing
  testEnvironment: "jsdom",

  moduleDirectories: ["node_modules", "src"],
  moduleNameMapper: {
    "^@/(.*)$": ['<rootDir>/$1'],

    // https://github.com/jestjs/jest/issues/12036
    '^d3-(.+)$': '<rootDir>/node_modules/d3-$1/dist/d3-$1.js',
  },

  setupFiles: ['<rootDir>/setup-jest.ts'],

  preset: 'ts-jest',

  // Ignore node_modules, EXCEPT the ones listed here
  transformIgnorePatterns: ['/node_modules/(?!(p-queue|p-timeout|mui-sonner|d3-scale)/)']
};

// next adds /node_modules/ to the start of the ignore list, which we need to remove
// in order to add exceptions
function createModifiedJestConfig(jestConfig) {
  return async () => {
    const nextConfig = await createJestConfig(jestConfig)();

    nextConfig.transformIgnorePatterns =
      nextConfig.transformIgnorePatterns.filter((path) => path !== '/node_modules/');

    return nextConfig;
  };
}

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