Example definitions file

definition.d.lua

-- This represents a type.
-- It isn't exported into the global environment unless it has `export` before the name.
export type ExampleType = {
    example_field: string,
    example_method: (any) -> string
}

-- This represents a global table, rather than a type
declare ExampleLibrary: {
    function_name: (any) -> string
}

-- This represents a global variable.
declare ExampleGlobal: ExampleType

-- This represents a global function.
-- The entirety of Luau's type system can be used, but a generic is used to demonstrate that.
declare function ExampleGlobalFunction<T>(param_name: T): T

-- This represents a 'class'. It can be inherited from.
declare class ExampleClass
    -- For reasons known only to Roblox, there are no commas after class entries.
    example_class_field: ExampleType
    example_class_function: (any) -> ()
    example_class_method: (ExampleClass) -> ()
end

-- Classes can be extended.
declare class ExampleExtension extends ExampleClass
    example_extension: ExampleClass
end

... there are no comments after class entries.

*commas

:)