paths-to-module-name-mapper.js

const pathsToModuleNameMapper = require('../paths-to-module-name-mapper')

const tsconfigMap = {
  log: ['src/utils/log'],
  server: ['src/server'],
  client: ['src/client', 'src/client/index'],
  'util/*': ['src/utils/*'],
  'api/*': ['src/api/*'],
  'test/*': ['test/*'],
  'mocks/*': ['test/mocks/*'],
  'test/*/mock': ['test/mocks/*', 'test/__mocks__/*'],
  '@foo-bar/common': ['../common/dist/library'],
  '@pkg/*': ['./packages/*'],
}

describe('pathsToModuleNameMapper', () => {
  test('should convert tsconfig mapping with no given prefix', () => {
    expect(pathsToModuleNameMapper(tsconfigMap)).toMatchInlineSnapshot(`
      Object {
        "^@foo\\\\-bar/common$": "../common/dist/library",
        "^@pkg/(.*)$": "./packages/$1",
        "^api/(.*)$": "src/api/$1",
        "^client$": Array [
          "src/client",
          "src/client/index",
        ],
        "^log$": "src/utils/log",
        "^mocks/(.*)$": "test/mocks/$1",
        "^server$": "src/server",
        "^test/(.*)$": "test/$1",
        "^test/(.*)/mock$": Array [
          "test/mocks/$1",
          "test/__mocks__/$1",
        ],
        "^util/(.*)$": "src/utils/$1",
      }
    `)
  })

  test('should add `js` extension to resolved config with useESM: true', () => {
    expect(pathsToModuleNameMapper(tsconfigMap, {useESM: true})).toEqual({
      /**
       * Why not using snapshot here?
       * Because the snapshot does not keep the property order, which is important for jest.
       * A pattern ending with `\\.js` should appear before another pattern without the extension does.
       */
      '^log$': 'src/utils/log',
      '^server$': 'src/server',
      '^client$': ['src/client', 'src/client/index'],
      '^util/(.*)\\.js$': 'src/utils/$1',
      '^util/(.*)$': 'src/utils/$1',
      '^api/(.*)\\.js$': 'src/api/$1',
      '^api/(.*)$': 'src/api/$1',
      '^test/(.*)\\.js$': 'test/$1',
      '^test/(.*)$': 'test/$1',
      '^mocks/(.*)\\.js$': 'test/mocks/$1',
      '^mocks/(.*)$': 'test/mocks/$1',
      '^test/(.*)/mock\\.js$': ['test/mocks/$1', 'test/__mocks__/$1'],
      '^test/(.*)/mock$': ['test/mocks/$1', 'test/__mocks__/$1'],
      '^@foo\\-bar/common$': '../common/dist/library',
      '^@pkg/(.*)\\.js$': './packages/$1',
      '^@pkg/(.*)$': './packages/$1',
      '^(\\.{1,2}/.*)\\.js$': '$1',
    })
  })

  test.each(['<rootDir>/', 'foo'])(
    'should convert tsconfig mapping with given prefix',
    prefix => {
      expect(pathsToModuleNameMapper(tsconfigMap, {prefix})).toMatchSnapshot(
        prefix,
      )
    },
  )

  describe('warnings', () => {
    beforeEach(() => {
      jest.spyOn(console, 'warn').mockImplementation()
    })

    afterEach(() => jest.mocked(console.warn).mockRestore())

    test('should warn about mapping it cannot handle', () => {
      expect(
        pathsToModuleNameMapper({
          kept: ['src/kept'],
          'no-target': [],
          'too/*/many/*/stars': ['to/*/many/*/stars'],
        }),
      ).toMatchInlineSnapshot(`
        Object {
          "^kept$": "src/kept",
        }
      `)

      expect(jest.mocked(console.warn)).toHaveBeenCalledWith(
        'Not mapping "no-target" because it has no target.',
      )
      expect(jest.mocked(console.warn)).toHaveBeenCalledWith(
        'Not mapping "too/*/many/*/stars" because it has more than one star (`*`).',
      )
    })
  })
})