Angular 12: Don't include deprecated TSLint by default

[prabh-62]

🐞 Bug report

Command (mark with an x)

• new
• build
• serve
• test
• e2e
• generate
• add
• update
• lint
• extract-i18n
• run
• config
• help
• version
• doc

Is this a regression?

Not applicable

Description

• TSLint has been deprecated since January 1st, 2020

- As such, TSLint should not be included by default in Angular projects

🔬 Minimal Reproduction

• (Optional) Create global angular config file to use yarn package manager if not present. cat ~/.angular-config.json

  {
   "version": 1,
   "cli": {
     "packageManager": "yarn"
   }
  }

• npx @angular/cli@12.0.0-next.1 new web-apps --create-application false
• Open package.json

   {
     "devDependencies": {
       "tslint": "~6.1.0"
     }
   }

🌍 Your Environment

❯ ng version

     _                      _                 ____ _     ___
    / \   _ __   __ _ _   _| | __ _ _ __     / ___| |   |_ _|
   / △ \ | '_ \ / _` | | | | |/ _` | '__|   | |   | |    | |
  / ___ \| | | | (_| | |_| | | (_| | |      | |___| |___ | |
 /_/   \_\_| |_|\__, |\__,_|_|\__,_|_|       \____|_____|___|
                |___/
    

Angular CLI: 12.0.0-next.1
Node: 15.9.0
OS: darwin x64 (11.2.1)
Yarn: cd web-apps` && `yarn outdated

Angular: 12.0.0-next.1
... animations, cli, common, compiler, compiler-cli, core, forms
... platform-browser, platform-browser-dynamic, router
Ivy Workspace: Yes

Package                      Version
------------------------------------------------------
@angular-devkit/architect    0.1200.0-next.1
@angular-devkit/core         12.0.0-next.1
@angular-devkit/schematics   12.0.0-next.1
@schematics/angular          12.0.0-next.1
@schematics/update           0.1200.0-next.1
rxjs                         6.6.3
typescript                   4.1.5

Anything else relevant?

Not relevant to this issue

• Thank you to the team for making strict option the default when creating applications (starting Angular 12)

[rgant]

Not having a linter included with angular cli by default would make my life trying to help people work with Angular much more difficult.

[MuhAssar]

why not just replacing it with eslint

[kyliau]

We will stop generating new projects with TSLint starting version 12.
The TSLint builder has already been deprecated in version 11, actual removal will be in version 13.
When running ng lint in version 12, CLI will print out commands to inform users third party alternatives that they can install on their own, much like the behavior of ng deploy.
As for replacing TSLint with something else by default, we'll let users make the call because existing solutions are all community owned, and our team does not have the resources to maintain and provide support for third party builders.
One of our major concerns is that adding third party builders to CLI could potentially increase the number of transitive dependencies by a lot, and hence massively increase the download size of Angular CLI.
For these reasons, we think it's best to leave the decision to users.

[prabh-62]

Is codelyzer package also not going to be included by default?

[alan-agius4]

Yeah, codelyzer is only used with tslint, hence when removing tslint we will also remove it.