Add "check-type-operator" option for whitespace rule

[santialbo]

PR checklist

• Addresses an existing issue: Add "check-type-operator" option for whitespace rule #488, Extend whitespace rule for pipe check #2818
• New feature, bugfix, or enhancement
  • Includes tests
• Documentation update

Overview of change:

This PR adds the "check-type-operator" option to the whitespace rule. The implementation is very similar to the binary operator one.

Is there anything you'd like reviewers to focus on?

CHANGELOG.md entry:

[new-rule-option] check-type-operator for whitepace rule

[palantirtech]

Thanks for your interest in palantir/tslint, @santialbo! Before we can accept your pull request, you need to sign our contributor license agreement - just visit https://cla.palantir.com/ and follow the instructions. Once you sign, I'll automatically update this pull request.

[ajafff]

This change looks very familiar to me. I think I've seen a similar PR before, but cannot find it right now.

Btw. that's not a type operator (IIRC keyof T is a type operator - at least in the AST)

[santialbo]

maybe you've seen this https://github.com/Microsoft/TypeScript/blob/master/scripts/tslint/typeOperatorSpacingRule.ts

[ajafff]

Got it: #2884

[santialbo]

Yup, it does pretty much the same. Looking at the changes I noticed the other PR is not checking for the option to be true.
Also the reason I called them type operators is because of the rule in the typescript repo I mentioned before.

[ajafff]

You're right. Added a comment over there.

Re type operator: unfortunately that could lead to confusion with the typescript spec where type operator refers to something completely different

[adidahiya]

The spec currently refers to them as operators, so I think this naming is better than "type list".

[santialbo]

Rebased with latest master, I think the CI error is unrelated to this PR.

[ajafff]

Do we also want to add this to tslint:latest?

[adidahiya]

yes please

[adidahiya]

I'll do it in a separate PR

[adidahiya]

your code looks good @santialbo, I'm fixing the master build here #3118