为什么Jest 24.8 Coverage产生coverage === 0

Question

 PASS  ../parser/test/flatten-user-flow-shortcuts.spec.ts
 PASS  ../parser/test/flow-spliterators.spec.ts
 PASS  ../parser/test/circles1.spec.js
 PASS  ../parser/test/circles.spec.ts
 PASS  ../parser/test/replace-basic-flows.spec.ts
 PASS  ../parser/test/multiple-flows-in-first-layer.spec.ts
 PASS  ../parser/test/multiple-layers.spec.ts
 PASS  ../parser/test/extends-basic-flows.spec.ts

----------|----------|----------|----------|----------|-------------------|
File      |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
----------|----------|----------|----------|----------|-------------------|
All files |        0 |        0 |        0 |        0 |                   |
----------|----------|----------|----------|----------|-------------------|

jest.config.js

module.exports = {
  testEnvironment: 'node',
  modulePaths: resolveModulesPathsArray,
  testRegex: [`./*.spec.js$`, `./*.spec.ts$`],
  roots: [mainTestsFolderPath, srcPath],
  transform: { '^.+\\.js$': jestTransformerFilePath, '^.+\\.ts$': jestTransformerFilePath },
  testPathIgnorePatterns: [`coverage`, 'node_modules'],
  setupFiles: [testPolyfillsFilePath],
  moduleFileExtensions: ['ts', 'tsx', 'js', 'jsx', 'json'],
  collectCoverage: true,
  collectCoverageFrom: [`${srcPath}/*.{ts,tsx,js,jsx,json}`],
}

srcPath是我的src文件夹的绝对路径。

我的问题

我确定我忘了配置一些东西。在运行"test": "react-scripts test --coverage",时，我什至在一个新的create-react-app中检查了这一点，并且看到了相同的结果。

是什么原因造成的？