Jest 测试失败:SyntaxError: Unexpected token < [英] Jest test fail: SyntaxError: Unexpected token <

问题描述

不知道去哪里寻找这个错误.

Not sure where to look for this error.

将 Typescript 与 React、Jest 和 Enzyme 结合使用进行单元测试.

Using Typescript with React, and Jest and Enzyme for unit testing.

Package.json 示例:

Package.json sample:

"scripts": {
    "start": "node server.js",
    "bundle": "cross-env NODE_ENV=production webpack -p",
    "test": "jest"
  },
  "jest": {
    "transform": {
      "^.+\.tsx?$": "<rootDir>/node_modules/ts-jest/preprocessor.js"
    },
    "testRegex": "(/__tests__/.*|\.(test|spec))\.(ts|tsx|js)$",
    "moduleFileExtensions": [
      "ts",
      "tsx",
      "js",
      "json"
    ]
  }

运行 npm 测试结果:

Running npm test results in:

FAIL src/components/Component.test.tsx

 ({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,global,jest){<?xml version="1.0" encoding="UTF-8"?>
                                                                                             ^

    SyntaxError: Unexpected token <

它似乎发生在我使用 require 加载静态 .svg 文件的第一个地方.为什么它不能处理?有没有办法在使用 require 时忽略抛出这个错误?

It appears to be happening the first place where i use require to load a static .svg file. Why can it not handle that? Is there a way to ignore throwing this error when using require?

推荐答案

Jest 不使用 Webpack，因此它不知道如何加载 js/jsx 以外的其他文件扩展名.要添加对其他扩展的支持，您需要编写自定义转换器.其中一个转换器是您在此片段的配置中定义的 Typescript 转换器:

Jest doesn't use Webpack so it doesn't know how to load other file extensions than js/jsx. To add support for other extensions you need to write custom transformers. One of the transformers is a Typescript transformer which you have defined in your configuration in this fragment:

"transform": {
   "^.+\.tsx?$": "<rootDir>/node_modules/ts-jest/preprocessor.js"
},

现在您需要为 svg 文件添加转换器.让我们扩展你的笑话配置

Now you need to add transformer for svg files. Let's extend your jest config

"transform": {
       "^.+\.tsx?$": "<rootDir>/node_modules/ts-jest/preprocessor.js",
       "^.+\.svg$": "<rootDir>/svgTransform.js" 
    },

并在您的根目录中创建具有以下内容的 svgTransform.js 文件

and create the svgTransform.js file in your root directory with the following content

module.exports = {
  process() {
    return 'module.exports = {};';
  },
  getCacheKey() {
    // The output is always the same.
    return 'svgTransform';
  },
};

当然，这是一个返回相同值的基本转换器.

Of course, it's a basic transformer that returns always the same value.

文档链接:http://facebook.github.io/jest/docs/en/configuration.html#transform-object-string-string

这篇关于Jest 测试失败:SyntaxError: Unexpected token <的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！