节点模块导出，访问不存在的属性错误，Jasmine

Posted 2023-03-07

【中文标题】节点模块导出，访问不存在的属性错误，Jasmine

【英文标题】：node module exports, Accessing non-existent property error, Jasmine

【发布时间】：2021-09-29 19:51:18

【问题描述】：

我正在使用客户的遗留代码，它是一个用于 Jasmine 测试的 node.js 项目。 我的问题是，当我运行测试时，调用的函数（在不同的文件中）找不到/查看使用require导入文件的特定方法

示例：

file1.js

const file2 = require('./file2');

fdescribe('Login', file2.login);

file2.js

const Api = require('./api');

module.exports = 
  login() 
    let user;
    beforeAll(async () => 
     user = await Api.createUser(
      first_name: 'login test',
      password: 'XXXX',
      ,
      Api.USER_ROLE.ADMIN);
    // more code within function...
    );
  // other functions

通过 IDE (VSCode)，所有路径都是完整的，可以在后面加上“转到定义”。另外作为测试，我将登录功能的内容放入 file1.js 的描述块中，更新依赖关系，一切正常。但是我的老板和客户希望保持目前的结构。

当我按此处所示运行时，我收到以下警告：

(node:6021) Warning: Accessing non-existent property 'createUser' of module exports inside circular dependency
(node:6021) Warning: Accessing non-existent property 'USER_ROLE' of module exports inside circular dependency

代码运行，但 createUser 和 USER_ROLE 出现“无法读取未定义的属性”错误。 我知道警告提到了循环依赖，但据我所知没有，即只有 1->2->Api-> 等。

当从 file1.js 调用 file2.js 中的函数时，似乎 file2.js 中的 require 没有发生。

在没有更多高级支持的情况下，我相当初级/缺乏经验，因此我在这里联系，可能是一个相当简单的问题。

项目正在运行node version 14.17.0

Api.js 文件更像是一个库文件，它“链接”到本例中包含 createUser 和 USER_ROLE 的其他文件。 [因为这是遗留的客户端代码，并且它在过去的某个时候工作过，我认为这可能与 Jasmine 或 Node JS 版本有关？]

节点警告/错误的更多细节：

(node:1693) Warning: Accessing non-existent property 'createUser' of module exports inside circular dependency
    at emitCircularRequireWarning (internal/modules/cjs/loader.js:675:11)
    at Object.get (internal/modules/cjs/loader.js:689:5)
    at UserContext.<anonymous> (/home/runner/work/platform-validation/platform-validation/utils/dupes.js:45:24)
    at QueueRunner.attempt (/home/runner/work/platform-validation/platform-validation/node_modules/jasmine-core/lib/jasmine-core/jasmine.js:7756:40)
    at QueueRunner.run (/home/runner/work/platform-validation/platform-validation/node_modules/jasmine-core/lib/jasmine-core/jasmine.js:7798:25)
  SYS.20: Login
    ✗ User can login
      - TypeError: Cannot read property 'login' of undefined
    at runNext (/home/runner/work/platform-validation/platform-validation/node_modules/jasmine-core/lib/jasmine-core/jasmine.js:7715:18)
    at next (/home/runner/work/platform-validation/platform-validation/node_modules/jasmine-core/lib/jasmine-core/jasmine.js:7722:11)
    at QueueRunner.onComplete (/home/runner/work/platform-validation/platform-validation/node_modules/jasmine-core/lib/jasmine-core/jasmine.js:7615:9)
    at Immediate.<anonymous> (/home/runner/work/platform-validation/platform-validation/node_modules/jasmine-core/lib/jasmine-core/jasmine.js:7814:12)
    at processImmediate (internal/timers.js:464:21)
(node:1693) Warning: Accessing non-existent property 'USER_ROLE' of module exports inside circular dependency
    at emitCircularRequireWarning (internal/modules/cjs/loader.js:675:11)
    at Object.get (internal/modules/cjs/loader.js:689:5)
    at UserContext.<anonymous> (/home/runner/work/platform-validation/platform-validation/utils/dupes.js:49:11)
    at QueueRunner.attempt (/home/runner/work/platform-validation/platform-validation/node_modules/jasmine-core/lib/jasmine-core/jasmine.js:7756:40)
    at QueueRunner.run (/home/runner/work/platform-validation/platform-validation/node_modules/jasmine-core/lib/jasmine-core/jasmine.js:7798:25)
    at runNext (/home/runner/work/platform-validation/platform-validation/node_modules/jasmine-core/lib/jasmine-core/jasmine.js:7715:18)
    at next (/home/runner/work/platform-validation/platform-validation/node_modules/jasmine-core/lib/jasmine-core/jasmine.js:7722:11)
    at QueueRunner.onComplete (/home/runner/work/platform-validation/platform-validation/node_modules/jasmine-core/lib/jasmine-core/jasmine.js:7615:9)
    at Immediate.<anonymous> (/home/runner/work/platform-validation/platform-validation/node_modules/jasmine-core/lib/jasmine-core/jasmine.js:7814:12)
    at processImmediate (internal/timers.js:464:21)

【问题讨论】：

Node 抱怨未定义的属性是什么？如果是createUser 和USER_ROLE，最好检查一下你的 api.js 文件

【参考方案1】：

解决方案是添加：delete require.cache[require.resolve('./api')] 在file2.js 中的const Api = require('./api'); 之前 这与 Node 缓存 require() 调用而不是按预期重新调用有关。

更多解释见链接：

How to remove module after "require" in node.js?

node.js require() cache - possible to invalidate?