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Type narrowing for unioned classes

Open CodeGreen0386 opened this issue 2 years ago • 3 comments

I have a large number of classes that look something like this:

---@class Foo
---@field type "foo"
---@field name string
---@field property string
-- more unique fields

---@class Bar
---@field type "bar"
---@field name string
---@field stuff string
-- more unique fields

-- more classes

I have a function that takes an array of any of these classes as a parameter, so naturally I've unioned all of the classes.

---@alias Prototypes
---|Foo
---|Bar
-- all of the other classes

---@param prototypes Prototypes[]
local function extend(prototypes)
  -- stuff and things
end

However, when I try to make prototypes a table literal, I get autocomplete for the other classes because the union operator behaves like intersection instead of union.

image

Is there any way to get it to show only the fields of the class indicated by the type field? I can't seem to find way to do a proper union of types. @type seems to only work on variables, and even if it did work on table literals, it would be cumbersome to write out the type for every entry in the array.

CodeGreen0386 avatar May 14 '23 04:05 CodeGreen0386