[mobx-keystone] a model with name "PageModel" already exists (if you are using hot-reloading you may safely ignore this warning)

[airtonix]

I know it was mentioned (vaguely) here that avoiding the "Model already exists" warning in jest involves globalConfig, however being the absolute novice (at least compared to @xaviergonz) that I am, perhaps I am DoingItWrong(tm):

Everyone of our models that ends up involved in a test throws a warning that is some variation of this:

  console.warn
    [mobx-keystone] a model with name "AttachmentFieldModel" already exists (if you are using hot-reloading you may safely ignore this warning)

      24 |  */
      25 | @model(ATTACHMENTFIELD_MODEL_KEY)
    > 26 | export class AttachmentFieldModel extends ExtendedModel(BaseFieldModel, {

My jest setup:

src/
  store/
   **/*
jest.config.js
jest.config.beforeeach.js
jest.config.beforeeach-mobxkeystone.js
jest.config.setup-enzyme.js
jest.config.setup-mobxkeystone.js
jest.config.setup-polyfills.js

// jest.config.js
...

  globals: {
    keystoneCounter: 0
  },

  setupFilesAfterEnv: [
    `<rootDir>/packages/${packageName}/jest.config.beforeeach.ts`,
    `<rootDir>/packages/${packageName}/jest.config.beforeeach-mobxkeystone.js`,
  ],

  setupFiles: [
    `<rootDir>/packages/${packageName}/jest.config.setup-enzyme.js`,
    `<rootDir>/packages/${packageName}/jest.config.setup-polyfills.js`,
    `<rootDir>/packages/${packageName}/jest.config.setup-mobxkeystone.js`,
  ],
...

// jest.config.setup-mobxkeystone.js

import { setGlobalConfig } from 'mobx-keystone'

global.keystoneCounter = 1

setGlobalConfig({
  modelIdGenerator () {
    return `id-${global.keystoneCounter++}`
  },
})

// jest.config.beforeeach-mobxkeystone.js
global.keystoneCounter = 1

If i throw a dirty console log in that modelIdGenerator, then I see a lot of expected spam in the console that the generated id is always 1 since none of our tests cases instantiate more than one instance of a model yet.

If i remove the jest.config.beforeeach-mobxkeystone.js logic, then the model count logged in the console grows as expected, but the error/warning still remains.

Any thoughts/help on properly utilising setGlobalConfig ?

[airtonix]

I will also mention that i've split jest.config.before-mobxkeystone.js and jest.config.setup-mobxkeystone.js in the jest config because you're don't have access to beforeEach within the setupFiles stage.

[airtonix]

I've also had a look at https://github.com/xaviergonz/mobx-keystone/blob/master/packages/lib/test/commonSetup.ts and tried to imitate its use, but we still get the error/warning mentioned above.

[xaviergonz]

Does it happen when jest is running in watch mode, when it runs in single run mode or both?

[xaviergonz]

Btw, the model Id generator is what generates $modelId keys, so it is totally unrelated to the warning you get.

Also, I just added showDuplicateModelNameWarnings to the global config in v0.48.2, which you can set to false to get rid of those warnings in testing envs (such as jest).

[airtonix]

@xaviergonz I'll give that a whirl.

also:

• yes it happens in watch mode and single run.
• I'm sure it's not a deal breaker, they're only warnings... just noisy.

[airtonix]

fixed! legend.