jest.config.js

module.exports = {
  // The root of your source code, typically /src
  // `<rootDir>` is a token Jest substitutes
  roots: ['<rootDir>/src'],

  // Jest transformations -- this adds support for TypeScript
  // using ts-jest
  transform: {
    '^.+\\.tsx?$': 'ts-jest',
    '^.+\\.ts?$': 'ts-jest',
    '^.+\\.(jpg|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$': '<rootDir>/svgTransform.js'
  },
  // testPathIgnorePatterns: ['./node_modules/'],
  // Test spec file resolution pattern
  // Matches parent folder `__tests__` and filename
  // should contain `test` or `spec`.
  testRegex: '(/__tests__/.*|(\\.|/)(test|spec))\\.tsx?$',

  // Module file extensions for importing
  moduleFileExtensions: ['ts', 'tsx', 'js', 'jsx', 'json', 'node'],
  moduleNameMapper: {
    '^@/(.*)$': '<rootDir>/src/$1',
    '^.+\\.(css|less|scss)$': 'babel-jest',
    d3: '<rootDir>/node_modules/d3/dist/d3.min.js'
  },
  testEnvironment: 'jsdom',
  setupFilesAfterEnv: ['<rootDir>/setupTests.ts']
};