Joi: Joi import fails with Method Map.prototype.set called on incompatible receiver #<Map>

[klesgidis]

Support plan

• which support plan is this issue covered by? (e.g. Community, Core, Plus, or Enterprise): Community
• is this issue currently blocking your project? (yes/no): yes
• is this issue affecting a production system? (yes/no): no

Context

• node version: v12.11.1
• module version: v17.1.1
• environment (e.g. node, browser, native): node
• used with (e.g. hapi application, another framework, standalone, ...): standalone
• any other relevant information: I am using typescript & jest

How can we help?

Hi guys, I have a really strange issue and I am not able to understand what is going on.

I am trying to run unit tests with jest (v25.3.0). While I am importing @hapi/joi in one of my node files I get the following error:

  ● Test suite failed to run

    TypeError: Method Map.prototype.set called on incompatible receiver #<Map>
        at Map.set (<anonymous>)

      at Object.<anonymous>.module.exports.internals.clone (../node_modules/@hapi/hoek/lib/clone.js:74:20)
      at Object.<anonymous>.module.exports.internals.clone (../node_modules/@hapi/hoek/lib/clone.js:99:31)
      at Object.<anonymous>.module.exports.internals.clone (../node_modules/@hapi/hoek/lib/clone.js:99:31)
      at Object.<anonymous>.module.exports.internals.clone (../node_modules/@hapi/hoek/lib/clone.js:99:31)
      at Object.<anonymous>.module.exports.internals.clone (../node_modules/@hapi/hoek/lib/clone.js:99:31)
      at Object.<anonymous>.exports.type (../node_modules/@hapi/joi/lib/extend.js:16:23)
      at Object.<anonymous>.internals.Base.extend (../node_modules/@hapi/joi/lib/base.js:437:23)
      at Object.<anonymous> (../node_modules/@hapi/joi/lib/types/alternatives.js:15:22)
      at Object.<anonymous> (../node_modules/@hapi/joi/lib/index.js:21:23)
      at Object.<anonymous> (app/controllers/v1/file-controller.ts:1353:41)

No test is running before the failure. The line in app/controllers/v1/file-controller.ts that is causing the issue is import * as Joi from '@hapi/joi';

Do you have any idea why this is happening, because I am stuck

[kanongil]

Hoek has some specific logic to handle cloning maps. From the error, it seems that this logic is somehow circumvented. Probably due to something the typescript compiler jest does.

[ecoulson]

Hey I am encountering the same error, when I clear my jest mocks the code executes. Have you found a solution to this issue?

Edit:

Based off of what kanongil said, the Map object maybe getting mocked by jest?

[ecoulson]

I found out that the issue is that the Map object is being mocked by Jest. I found that the Map class becomes mocked when I make a call to mock a mongoose model using jest.mock(...). I solved this issue by passing a factory argument to the jest.mock function that created my mongoose models without touching the Map class. All of my tests seem to be passing fine now.

[derkinderfietsen]

@ecoulson I'm having the same issue here, could you please explain a bit more about the solution?

[ptrin]

@ecoulson I'd also really like a little more detail on how you worked around this if it isn't too much trouble :)

[auzwang]

@ptrin @derkinderfietsen here's what's happening:

file-controller.ts will be importing a mongoose model such as ../model/file.ts.

Then inside file-controller.test.ts, that model would be mocked using an automatic mock.

...
jest.mock('../../model/file.ts') // automatic mock inadvertently mocks Map
...
describe('file controller', () => {
  test('deletes file', async () => {
    await fileController.delete('filename') // this calls `model/file.ts`'s delete method
  })
  ...
})

What @ecoulson did was explicitly mock the used methods on model/file.ts using the a module factory.

...
jest.mock('../../model/file.ts', () => ({ delete: jest.fn() })) // Map no longer mocked
...
describe('file controller', () => {
  test('deletes file', async () => {
    await fileController.delete('filename') // this calls `model/file.ts`'s delete method
  })
  ...
})

[ptrin]

@auzwang Thanks, that's very helpful!