feat: Temporal dates and times

src/Fable.AST/Plugins.fs

@@ -40,6 +40,7 @@ type CompilerOptions =
         FileExtension: string
         TriggeredByDependency: bool
         NoReflection: bool
+        JsTemporal: bool
     }
 
 type PluginHelper =

src/Fable.Cli/Entry.fs

@@ -126,6 +126,7 @@ let knownCliArgs () =
         [ "--trimRootModule" ], []
         [ "--fableLib" ], []
         [ "--replace" ], []
+        [ "--test:js-temporal" ], []
     ]
 
 let printKnownCliArgs () =
@@ -314,12 +315,16 @@ type Runner =
                 | Some c when String.IsNullOrWhiteSpace c -> defaultConfiguration
                 | Some configurationArg -> configurationArg
 
+            let jsTemporal = args.FlagEnabled "--test:js-temporal"
+
             let define =
                 args.Values "--define"
                 |> List.append
                     [
                         "FABLE_COMPILER"
                         "FABLE_COMPILER_5"
+                        if jsTemporal then
+                            "FABLE_COMPILER_JAVASCRIPT_TEMPORAL"
                         match language with
                         | Php -> "FABLE_COMPILER_PHP"
                         | Rust -> "FABLE_COMPILER_RUST"
@@ -353,7 +358,8 @@ type Runner =
                     debugMode = (configuration = "Debug"),
                     optimizeFSharpAst = args.FlagEnabled "--optimize",
                     noReflection = args.FlagEnabled "--noReflection",
-                    verbosity = verbosity
+                    verbosity = verbosity,
+                    jsTemporal = jsTemporal
                 )
 
             let cliArgs =

src/Fable.Transforms/Babel/Fable2Babel.fs

@@ -745,8 +745,16 @@ module Annotation =
         | Replacements.Util.BclTimeSpan -> NumberTypeAnnotation
         | Replacements.Util.BclDateTime -> makeAliasTypeAnnotation com ctx "Date"
         | Replacements.Util.BclDateTimeOffset -> makeAliasTypeAnnotation com ctx "Date"
-        | Replacements.Util.BclDateOnly -> makeAliasTypeAnnotation com ctx "Date"
-        | Replacements.Util.BclTimeOnly -> NumberTypeAnnotation
+        | Replacements.Util.BclDateOnly ->
+            if com.Options.JsTemporal then
+                makeFableLibImportTypeAnnotation com ctx [] "DateOnlyTemporal" "PlainDate"
+            else
+                makeAliasTypeAnnotation com ctx "Date"
+        | Replacements.Util.BclTimeOnly ->
+            if com.Options.JsTemporal then
+                makeFableLibImportTypeAnnotation com ctx [] "TimeOnlyTemporal" "PlainTime"
+            else
+                NumberTypeAnnotation
         | Replacements.Util.BclTimer -> makeFableLibImportTypeAnnotation com ctx [] "Timer" "Timer"
         | Replacements.Util.BclHashSet key -> makeFableLibImportTypeAnnotation com ctx [ key ] "Util" "ISet"
         | Replacements.Util.BclDictionary(key, value) ->
@@ -3511,11 +3519,13 @@ but thanks to the optimisation done below we get
             | Fable.Char -> Expression.stringLiteral "\u0000"
             | Fable.Number(kind, uom) ->
                 com.TransformAsExpr(ctx, Fable.NumberConstant(Fable.NumberValue.GetZero kind, uom) |> makeValue None)
+            | Builtin BclTimeOnly when com.Options.JsTemporal ->
+                libCall com ctx None "TimeOnlyTemporal" "minValue" [] []
             | Builtin(BclTimeSpan | BclTimeOnly) -> Expression.numericLiteral 0
             | Builtin BclGuid -> Expression.stringLiteral "00000000-0000-0000-0000-000000000000"
             | Builtin BclDateTime -> libCall com ctx None "Date" "minValue" [] []
             | Builtin BclDateTimeOffset -> libCall com ctx None "DateOffset" "minValue" [] []
-            | Builtin BclDateOnly -> libCall com ctx None "DateOnly" "minValue" [] []
+            | Builtin BclDateOnly -> libCall com ctx None (JS.Replacements.dateOnlyModule com) "minValue" [] []
             | _ -> libCall com ctx None "Util" "defaultOf" [] []
 
     let getEntityFieldsAsIdents (ent: Fable.Entity) =

src/Fable.Transforms/Global/Compiler.fs

@@ -18,7 +18,8 @@ type CompilerOptionsHelper =
             ?verbosity,
             ?fileExtension,
             ?clampByteArrays,
-            ?noReflection
+            ?noReflection,
+            ?jsTemporal
         )
         =
         {
@@ -32,6 +33,7 @@ type CompilerOptionsHelper =
             ClampByteArrays = defaultArg clampByteArrays false
             NoReflection = defaultArg noReflection false
             TriggeredByDependency = false
+            JsTemporal = defaultArg jsTemporal false
         }
 
 [<RequireQualifiedAccess>]