Array-based List type

Author: ncave

src/Fable.Transforms/Fable2Babel.fs

@@ -932,24 +932,36 @@ module Util =
         // | Fable.NewList (headAndTail, _) when List.contains "FABLE_LIBRARY" com.Options.Define ->
         //     makeList com ctx r headAndTail
         // Optimization for bundle size: compile list literals as List.ofArray
+        | Replacements.ListLiteral(exprs, t) ->
+            [|List.rev exprs |> makeArray com ctx|]
+            |> libCall com ctx r "List" "newList"
+            // match exprs with
+            // | [] -> libCall com ctx r "List" "empty" [||]
+            // | [TransformExpr com ctx expr] -> libCall com ctx r "List" "singleton" [|expr|]
+            // | exprs -> [|makeArray com ctx exprs|] |> libCall com ctx r "List" "ofArray"
         | Fable.NewList (headAndTail, _) ->
-            let rec getItems acc = function
-                | None -> List.rev acc, None
-                | Some(head, Fable.Value(Fable.NewList(tail, _),_)) -> getItems (head::acc) tail
-                | Some(head, tail) -> List.rev (head::acc), Some tail
-            match getItems [] headAndTail with
-            | [], None ->
-                libCall com ctx r "List" "empty" [||]
-            | [TransformExpr com ctx expr], None ->
-                libCall com ctx r "List" "singleton" [|expr|]
-            | exprs, None ->
-                [|makeArray com ctx exprs|]
-                |> libCall com ctx r "List" "ofArray"
-            | [TransformExpr com ctx head], Some(TransformExpr com ctx tail) ->
+            match headAndTail with
+            | None -> libCall com ctx r "List" "empty" [||]
+            | Some(TransformExpr com ctx head, TransformExpr com ctx tail) ->
                 libCall com ctx r "List" "cons" [|head; tail|]
-            | exprs, Some(TransformExpr com ctx tail) ->
-                [|makeArray com ctx exprs; tail|]
-                |> libCall com ctx r "List" "ofArrayWithTail"
+
+            // let rec getItems acc = function
+            //     | None -> List.rev acc, None
+            //     | Some(head, Fable.Value(Fable.NewList(tail, _),_)) -> getItems (head::acc) tail
+            //     | Some(head, tail) -> List.rev (head::acc), Some tail
+            // match getItems [] headAndTail with
+            // | [], None ->
+            //     libCall com ctx r "List" "empty" [||]
+            // | [TransformExpr com ctx expr], None ->
+            //     libCall com ctx r "List" "singleton" [|expr|]
+            // | exprs, None ->
+            //     [|makeArray com ctx exprs|]
+            //     |> libCall com ctx r "List" "ofArray"
+            // | [TransformExpr com ctx head], Some(TransformExpr com ctx tail) ->
+            //     libCall com ctx r "List" "cons" [|head; tail|]
+            // | exprs, Some(TransformExpr com ctx tail) ->
+            //     [|makeArray com ctx exprs; tail|]
+            //     |> libCall com ctx r "List" "ofArrayWithTail"
         | Fable.NewOption (value, t) ->
             match value with
             | Some (TransformExpr com ctx e) ->