Jest无法找到相对于目录的预设"env"

Question

我正在尝试使用Jest来测试我的节点API.我有一个简单的npm脚本调用jest

{
  "scripts": {
    "start": "node server.js",
    "dev": "nodemon server.js",
    "test": "jest",
    "precommit": "lint-staged"
  },
  "dependencies": {
    "@koa/cors": "^2.2.1",
    "apollo-link-http": "^1.5.4",
    "apollo-server-koa": "^1.3.6",
    "axios": "^0.18.0",
    "dotenv": "^6.0.0",
    "graphql": "^0.13.2",
    "graphql-tools": "^3.0.4",
    "koa": "^2.5.1",
    "koa-bodyparser": "^4.2.1",
    "koa-router": "^7.4.0",
    "node-fetch": "^2.1.2"
  },
  "devDependencies": {
    "husky": "^0.14.3",
    "jest": "^23.3.0",
    "lint-staged": "^7.2.0",
    "nodemon": "^1.17.5",
    "prettier": "^1.13.7"
  },
  "lint-staged": {
    "gitDir": "./",
    "*.{js,json}": [
      "prettier --no-semi --print-width 140 --tab-width 2 --write",
      "git add"
    ]
  },
  "jest": {
    "bail": true,
    "verbose": true,
    "testMatch": [
      "<rootDir>/**/*.test.js"
    ]
  }
}

我在我的jest配置中package.json告诉jest要测试什么:

"jest": {
    "bail": true,
    "verbose": true,
    "testMatch": [
      "<rootDir>/**/*.test.js"
    ]
  }

在我的项目中,我根本没有使用babel,但出于某种原因,当我尝试运行我的一个测试时 ./test.test.js

test("Example test", () => {
  expect(true).toBe(true)
})

我收到以下错误:

$ jest
 FAIL  ./test.test.js
  ? Test suite failed to run

    Couldn't find preset "env" relative to directory "/Users/<myusername>/Projects"

      at node_modules/babel-core/lib/transformation/file/options/option-manager.js:293:19
          at Array.map (<anonymous>)
      at OptionManager.resolvePresets (node_modules/babel-core/lib/transformation/file/options/option-manager.js:275:20)
      at OptionManager.mergePresets (node_modules/babel-core/lib/transformation/file/options/option-manager.js:264:10)
      at OptionManager.mergeOptions (node_modules/babel-core/lib/transformation/file/options/option-manager.js:249:14)
      at OptionManager.init (node_modules/babel-core/lib/transformation/file/options/option-manager.js:368:12)
      at File.initOptions (node_modules/babel-core/lib/transformation/file/index.js:212:65)
      at new File (node_modules/babel-core/lib/transformation/file/index.js:135:24)
      at Pipeline.transform (node_modules/babel-core/lib/transformation/pipeline.js:46:16)

Test Suites: 1 failed, 1 total
Tests:       0 total
Snapshots:   0 total
Time:        7.563s
Ran all test suites.
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

我尝试添加一个babel env预设但仍然得到相同的错误.我认为我不应该只为测试添加一个babel配置.

我正在运行节点版本8.11.3和纱线,1.7.0并使用版本在项目中本地安装了jest^23.2.0

我怎么告诉开玩笑不要担心babel env？

Answer 1

babel-jest安装Jest时会自动添加.如果你不打算转换ES6代码(看起来像你的情况)可能只是重置配置:

// package.json
{
  "jest": {
    "transform": {}
  }
}