[naming-convention] modifier global - Allow selecting only global variables

[glen-84]

Similar to #2239.

I'd like to be able to do something similar to this, i.e.:

// require all global constants to be camelCase or UPPER_CASE
// all other variables and functions still need to be camelCase
{"selector": "variable", "modifiers": ["global", "const"], "format": ["camelCase", "UPPER_CASE"]}

[InsOpDe]

Its funny because the description of the naming-convention rule states

Additionally, a well-designed style guide can help communicate intent, such as by enforcing all private properties begin with an _, and all global-level constants are written in UPPER_CASE.

and yet its not able to enforce this rule

[bradzacher]

Happy to accept a PR if you want it.

[phaux]

Maybe the name "topLevel" or something similar would be more appropriate for the modifier? When I hear "global" I think something attached to the window object. The convention I personally use is to name every top level or exported const with upper snake case, but use camel case for the ones in blocks, functions, classes, etc.

[phaux]

Unless you actually meant "global" as in attached to the window, but then it can't be a "const" (at least in modules)

[bradzacher]

This should be relatively easy to do, if anyone wants to try.

• define a new modifier
• when you encounter a variable definition - get the scope (context.getScope())
• check scope.type is either global or module

[infacto]

Just to visualize a use case:

random-file.ts

// Global variable allowed to be UPPER_CASE.
const MY_VALUE = 42;

export class MyClass {
  public myMethod(): void {
    // This local const (variable) is NOT allowed.
    const ANOTHER_VALUE = 27;

    // This is allowed.
    const anotherValue = 13;
  }
}

Yes this is not really "global" But for the file scope. It depends on the build system and use of the files. So, we could name it "global".
I don't know if we should cover real global variables in e.g. the window object. Because it's unusual in TypeScript.

Since const has different meaning in TypeScript then in other languages. If a variable (let) is never reassigned const should be used. (rule prefer-const) I only want strictCamelCase for that variables. But allow UPPER_CASE for "real" constants and e.g. static readonly (which already work) The current workaround is either disallow it or allow both cases and mention it in the code reviews.