带有 Jest 的 TypeScript 无法检测到库

Question

Jest 似乎无法获取导入的库。我一直在阅读它并尝试各种选择。其中之一是this。但是，它们似乎都不起作用。

//xyz.ts

..
/* eslint-disable */
import * as csv from 'csv-stringify/sync';
/* eslint-enable */
..

运行 Jest 后：

Test suite failed to run

    Cannot find module 'csv-stringify/sync' from 'xyz.ts'

正在使用的库 - https://csv.js.org/stringify/。

我怀疑我做错了什么，因为如果我不禁用它的检查，即使 ESLint 也会抱怨它。

 Unable to resolve path to module 'csv-stringify/sync'  import/no-unresolved

图书馆的结构：

此外，如果我尝试导入为

import * as csv from 'csv-stringify/lib/sync';

然后我在运行 Jest 后收到此错误

Test suite failed to run

    Jest encountered an unexpected token

    Jest failed to parse a file. This happens e.g. when your code or its dependencies use non-standard JavaScript syntax, or when Jest is not configured to support such syntax.

    Out of the box Jest supports Babel, which will be used to transform your files into valid JS based on your Babel configuration.

    By default "node_modules" folder is ignored by transformers.

    Here's what you can do:
     • If you are trying to use ECMAScript Modules, see https://jestjs.io/docs/ecmascript-modules for how to enable it.
     • If you are trying to use TypeScript, see https://jestjs.io/docs/getting-started#using-typescript
     • To have some of your "node_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config.
     • If you need a custom transformation specify a "transform" option in your config.
     • If you simply want to mock your non-JS modules (e.g. binary assets) you can stub them out with the "moduleNameMapper" config option.

    You'll find more details and examples of these config options in the docs:
    https://jestjs.io/docs/configuration
    For information about custom transformations, see:
    https://jestjs.io/docs/code-transformation

    Details:

    <redacted>/node_modules/csv-stringify/lib/sync.js:2
    import { Stringifier } from './index.js';
    ^^^^^^

我想这里可能需要某种转换？

其他文件：

jest.config.js

module.exports = {
  // Root path
  roots: [''],
  // testMatch: ['**/__tests__/**/*.+(ts|tsx|js)', '**/?(*.)+(spec|test).+(ts|tsx|js)'],
  // Only test TS files, don't test JS
  testMatch: ['**/?(*.)+(spec|test).+(ts)'],
  transform: {
    '^.+\\.(ts|tsx)$': 'ts-jest',
  },
  //  Include below folders to be checked for modules
  moduleDirectories: ['node_modules', 'src'],
};

tsconfig.json

{
  "compilerOptions": {
    "module": "commonjs",
    "noImplicitReturns": true,
    "noUnusedLocals": true,
    "outDir": "lib",
    "sourceMap": true,
    "strict": true,
    "target": "es2017",
    "strictNullChecks": true
  },
  "compileOnSave": true,
  "include": [
    "coverage",
    "jest.config.js",
    "src",
    "test"
  ]
}

---

解决以下建议：

从 dist 导入它 - lib 是源（未编译的）文件，这就是您收到第二个错误的原因。

试过 cjs 和 esm - 都没有工作

import * as csv  from 'csv-stringify/dist/cjs/sync';
..

错误

 Error [ERR_PACKAGE_PATH_NOT_EXPORTED]: Package subpath './dist/cjs/sync' is not defined by "exports" 

您是否尝试过 import { stringify } from 'csv-stringify/sync';正如图书馆所建议的那样？

是的 - 我收到另一个错误。

 Error [ERR_PACKAGE_PATH_NOT_EXPORTED]: Package subpath './lib/sync' is not defined by "exports" in <redacted>/node_modules/csv-stringify/package.json

package.jsonexports 部分

  "exports": {
    ".": {
      "import": "./lib/index.js",
      "require": "./dist/cjs/index.cjs"
    },
    "./sync": {
      "import": "./lib/sync.js",
      "require": "./dist/cjs/sync.cjs"
    },
    "./browser/esm/": "./dist/esm/"
  }

Answer 1

ESM/CJS 导入系统可能存在问题..

尝试将Jest 配置为在jest.config.ts 中使用带有此添加的ESM：

  {
    // ...
    "extensionsToTreatAsEsm": [".ts"]
  }

如果失败，请尝试使用 CJS 导入样式 const { stringify } = require('csv-stringify/sync');