'styles' object key always sets its value as an array with Jest testing

[davideasaf]

Expected Behavior

When running a Jest test for an Angular application that was setup using the NX workspace, the key styles in any object should be allowed to be mutated.

Current Behavior

Running Jest tests for an Angular application that was setup using the NX workspace, the key styles in an object is always set to an array [].

Failure Information (for bugs)

Steps to Reproduce

1. Create a brand new nx-workspace with npx create-nx-workspace@8.4.12 test-workspace (I used latest at the time)
2. Make the below selections:
   1. angular
   2. test-workspace
   3. sass
   4. Yes
   

3. Run

cd nx-workspace

4. Change the apps/test-workspace/src/app/app.component.spec.ts file to only be the below:

describe('BIZARRE TEST', () => {
  it('', () => {
    const foo = { styles: 'hello world' };
    if (Array.isArray(foo.styles)) {
      console.log('THIS SHOULD NOT PRINT');
    }
    console.log('FOO IS:', foo);
    expect(Array.isArray(foo.styles)).toBe(false);
  });
});

5. Run

yarn test

6. Result: The test does not pass. This indicates that using styles as an object key always sets the value to [].

Other

• I have created a minimal Jest application to test if this issue was only relevant for Jest, but the issue was not present in Jest.
• Repo with above steps reproduced: https://github.com/davideasaf/nx-jest-bug

[vsavkin]

There are two issues here. The first one is that the jest builder always tries to include jest-preset-angular. So it is not possible to opt out. We should fix it.

Second is the actual issue with jest-preset-angular that thinks that all object primitives with "styles" are component decorators. That issue has to be fixed on the jest-preset-angular side.

As a workaround, you can do something like this: const foo = { ['styles']: 'hello world' };.

[jaysoo]

This should have been fixed in jest-preset-angular: thymikee/jest-preset-angular#261

[github-actions]

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