Feature Request: Provide an option to configure the presentation of Arrays

[whitneyit]

Suggestion

Provide an option to configure the presentation of Arrays.

🔍 Search Terms

• Array generics
• Array presentation
• Array<T>
• T[]

This suggestion is hard to search for ☹️

✅ Viability Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behaviour of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, new syntax sugar for JS, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

⭐ Suggestion

I would like to see an option that will allow for altering the presentation of Arrays.

📃 Motivating Example

When reading through type errors or hovering over source code in VS Code, I find it hard to easily distinguish between Arrays, Tuples, Arrays of Tuples, Tuples with Arrays in them etc.

I personally use linting rules so that I know that when I see a [ or ] in my source code, I am explicitly dealing with a Tuple.

For example, I find Array<[Array<T>]> far easier to quickly parse than [T[]][]. This may simply be attributed to my bias of writing code in the generic form. Though, this gets worse with increased levels of nesting.

🎨 Prior art

The tslint rule array-type can be used to enforce using the generic form of Array<T>. Secondarily, this rule was also ported as the @typescript/eslint rule array-type.

💻 Use Cases

I find hovering over my own code and seeing it presented differently a bit frustrating. Consider the following playground screenshot:

In addition toarray-types options of "array", "generic", "array-simple", a fourth option of "preserve" could be added which would address the screenshot above.

I would like to suggest the following option:

Flag	Type	Default value
--arrayType	"array" | "generic" | "array-simple" | "preserve"	"preserve"

[Jamesernator]

I'm definitely plus-one on this, although for code authored by the user I think it probably doesn't even need configuration, just show the type as authored rather than regenerating a presentation. i.e. If I write string[] show string[], if I write Array<string> show Array<string>.

Obviously this doesn't neccessarily work for library code, so an option would probably be necessary for that.