Beagle-Web-Core doesn't work with Angular 6

[Tiagoperes]

Beagle Web version:

Steps To Reproduce

1. Create a project with Angular 6
2. Install Beagle-Angular in the project
3. Create the Beagle config
4. Try to run it

The current behavior

The compilation will fail stating that @zup-it/beagle-web-core/beagle-tree/index.d.ts references the type Iterator with 3 arguments, but it accepts only 1.

It happens because beagle-web-core is compiled using a much more recent version of Typescript, one that automatically adds these unnecessary arguments to the Iterator, which is not supported by the Typescript version used by Angular 6.

The only safe way to compile code correctly for old versions of Angular is to downgrade the Typescript version used by the beagle-web-core to the same one used by Angular 6.

The expected behavior

Expected to compile successfully

[Tiagoperes]

As of october 2nd 2020, we decided not to support Angular 6.

By supporting Angular 7.0.0 and beyond, we need to support typescript version 3.1.1.

[Tiagoperes]

Today I tried to downgrade the typescript version to 3.1.1. Since lots of our dependencies depends on more recent versions of typescript, I had to also downgrade them, here's a summary:

• Jest: from 25.1 to 23.6
• Nock: from 12 to 10

This is about 2 years in time.

These changes required some code alterations that can be checked here: https://github.com/ZupIT/beagle-web-core/tree/fix/typescript-downgrade

I don't like downgrading so far into the past, but I was ok with it, considering our goal. I'm not ok with it now, I just saw that eslint doesn't work with typescript 3.1.1, at least not since the first release of @typescript/es-lint.

Not having eslint or using an alpha version of the plugin is a big no-no for me. For this reason, I will patch this problem for the next version and, later, I'll try to find a solution that doesn't involve downgrading anything.

[Tiagoperes]

This is a know issue for Typescript maintainers:

• Automatic Backward/Forward .d.ts compatibility system microsoft/TypeScript#31907
• Provide a back-compat mechanism for bundled .d.ts files in package.json microsoft/TypeScript#22605

[Tiagoperes]

I'm closing this issue since the problem with old versions of Angular has been solved. I opened a new issue stating the current problem which is guaranteeing our code is compatible with old versions of TS: #272