jest.preset.js

// @ts-check

const path = require('path');
const { pathsToModuleNameMapper } = require('ts-jest');

const tsConfig = require('./tsconfig.base.json');

const tsPathAliases = pathsToModuleNameMapper(tsConfig.compilerOptions.paths, {
  prefix: `<rootDir>/${path.relative(process.cwd(), __dirname)}/`,
});

/**
 * @type {import('@jest/types').Config.InitialOptions}
 */
const baseConfig = {
  transform: {
    '^.+\\.ts$': 'ts-jest',
  },
  testMatch: ['**/+(*.)+(spec|test).+(ts|js)?(x)'],
  moduleFileExtensions: ['ts', 'tsx', 'js', 'jsx', 'json'],
  testPathIgnorePatterns: ['/node_modules/', '/lib/', '/lib-commonjs/', '/dist/'],
  testEnvironment: 'jsdom',
  moduleNameMapper: { ...tsPathAliases },
  cacheDirectory: '<rootDir>/node_modules/.cache/jest',
  clearMocks: true,
  watchPlugins: ['jest-watch-typeahead/filename', 'jest-watch-typeahead/testname'],
  // OLD format for migration to jest 29 - TODO: migrate to new format . https://jestjs.io/blog/2022/04/25/jest-28#future
  snapshotFormat: {
    escapeString: true,
    printBasicPrototype: true,
  },
};

module.exports = {
  ...baseConfig,
  /* TODO: Update to latest Jest snapshotFormat
   * By default Nx has kept the older style of Jest Snapshot formats
   * to prevent breaking of any existing tests with snapshots.
   * It's recommend you update to the latest format.
   * You can do this by removing snapshotFormat property
   * and running tests with --update-snapshot flag.
   * Example: "nx affected --targets=test --update-snapshot"
   * More info: https://jestjs.io/docs/upgrading-to-jest29#snapshot-format
   */
  snapshotFormat: { escapeString: true, printBasicPrototype: true },
};