[JS/TS] Fix date formatting when repeating a format token more than the known format (example repeating 'd' more than 4 times)

src/Fable.Cli/CHANGELOG.md

@@ -21,6 +21,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * [JS/TS] Report an error at compilation time when trying to use `Async.RunSynchronously` (by @MangelMaxime)
 * [JS/TS] Fix short `DateTime` and `DateTimeOffset` short format strings (by @MangelMaxime)
 * [All] Don't scan system packages for plugins (by @MangelMaxime)
+* [JS/TS] Fix date formatting when repeating a format token more than the known format (example repeating 'd' more than 4 times) (by @MangelMaxime)
+* [Python] Fix date formatting when repeating a format token more than the known format (example repeating 'd' more than 4 times) (by @MangelMaxime)
 
 ## 5.0.0-alpha.10 - 2025-02-16
 

src/Fable.Compiler/CHANGELOG.md

@@ -21,6 +21,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * [JS/TS] Report an error at compilation time when trying to use `Async.RunSynchronously` (by @MangelMaxime)
 * [JS/TS] Fix short `DateTime` and `DateTimeOffset` short format strings (by @MangelMaxime)
 * [All] Don't scan system packages for plugins (by @MangelMaxime)
+* [JS/TS] Fix date formatting when repeating a format token more than the known format (example repeating 'd' more than 4 times) (by @MangelMaxime)
+* [Python] Fix date formatting when repeating a format token more than the known format (example repeating 'd' more than 4 times) (by @MangelMaxime)
 
 ## 5.0.0-alpha.10 - 2025-02-16
 

src/fable-library-py/fable_library/date.py

@@ -227,10 +227,8 @@ def date_to_string_with_custom_format(date: datetime, format: str, utc: bool) ->
                         result += localized_date.strftime("%d")
                     case 3:
                         result += short_days[day_of_week(localized_date)]
-                    case 4:
+                    case 4 | _:
                         result += long_days[day_of_week(localized_date)]
-                    case _:
-                        pass
             case "f":
                 token_length = parse_repeat_token(format, cursor_pos, "f")
                 cursor_pos += token_length
@@ -243,7 +241,7 @@ def date_to_string_with_custom_format(date: datetime, format: str, utc: bool) ->
                     case 7:
                         result += str(localized_date.microsecond).zfill(6).ljust(token_length, "0")
                     case _:
-                        pass
+                        raise Exception("Input string was not in a correct format.")
             case "F":
                 token_length = parse_repeat_token(format, cursor_pos, "F")
                 cursor_pos += token_length
@@ -261,16 +259,11 @@ def date_to_string_with_custom_format(date: datetime, format: str, utc: bool) ->
                         if value != 0:
                             result += str(value).zfill(6).rstrip("0")
                     case _:
-                        pass
+                        raise Exception("Input string was not in a correct format.")
             case "g":
                 token_length = parse_repeat_token(format, cursor_pos, "g")
                 cursor_pos += token_length
-                match token_length:
-                    case 1 | 2:
-                        result += "A.D."
-                    case _:
-                        pass
-
+                result += "A.D."
             case "h":
                 token_length = parse_repeat_token(format, cursor_pos, "h")
                 cursor_pos += token_length
@@ -280,20 +273,16 @@ def date_to_string_with_custom_format(date: datetime, format: str, utc: bool) ->
                         if h1Value == 0:
                             h1Value = 12
                         result += str(h1Value)
-                    case 2:
+                    case 2 | _:
                         result += localized_date.strftime("%I")
-                    case _:
-                        pass
             case "H":
                 token_length = parse_repeat_token(format, cursor_pos, "H")
                 cursor_pos += token_length
                 match token_length:
                     case 1:
                         result += str(localized_date.hour)
-                    case 2:
+                    case 2 | _:
                         result += localized_date.strftime("%H")
-                    case _:
-                        pass
             case "K":
                 token_length = parse_repeat_token(format, cursor_pos, "K")
                 cursor_pos += token_length
@@ -318,10 +307,8 @@ def date_to_string_with_custom_format(date: datetime, format: str, utc: bool) ->
                 match token_length:
                     case 1:
                         result += str(localized_date.minute)
-                    case 2:
+                    case 2 | _:
                         result += localized_date.strftime("%M")
-                    case _:
-                        pass
             case "M":
                 token_length = parse_repeat_token(format, cursor_pos, "M")
                 cursor_pos += token_length
@@ -332,30 +319,24 @@ def date_to_string_with_custom_format(date: datetime, format: str, utc: bool) ->
                         result += localized_date.strftime("%m")
                     case 3:
                         result += short_months[month(localized_date) - 1]
-                    case 4:
+                    case 4 | _:
                         result += long_months[month(localized_date) - 1]
-                    case _:
-                        pass
             case "s":
                 token_length = parse_repeat_token(format, cursor_pos, "s")
                 cursor_pos += token_length
                 match token_length:
                     case 1:
                         result += str(localized_date.second)
-                    case 2:
+                    case 2 | _:
                         result += localized_date.strftime("%S")
-                    case _:
-                        pass
             case "t":
                 token_length = parse_repeat_token(format, cursor_pos, "t")
                 cursor_pos += token_length
                 match token_length:
                     case 1:
                         result += localized_date.strftime("%p")[:1]
-                    case 2:
+                    case 2 | _:
                         result += localized_date.strftime("%p")
-                    case _:
-                        pass
             case "y":
                 token_length = parse_repeat_token(format, cursor_pos, "y")
                 cursor_pos += token_length

src/fable-library-ts/Date.ts

@@ -114,9 +114,8 @@ function dateToStringWithCustomFormat(date: Date, format: string, utc: boolean)
             result += shortDays[dayOfWeek(localizedDate)];
             break;
           case 4:
-            result += longDays[dayOfWeek(localizedDate)];
-            break;
           default:
+            result += longDays[dayOfWeek(localizedDate)];
             break;
         }
         break;
@@ -133,6 +132,8 @@ function dateToStringWithCustomFormat(date: Date, format: string, utc: boolean)
           // This is to have the same behavior as .NET when doing:
           // DateTime(1, 2, 3, 4, 5, 6, DateTimeKind.Utc).ToString("fffff") => 00000
           result += ("" + millisecond(localizedDate)).padEnd(tokenLength, "0");
+        } else {
+          throw "Input string was not in a correct format.";
         }
         break;
       case "F":
@@ -152,14 +153,14 @@ function dateToStringWithCustomFormat(date: Date, format: string, utc: boolean)
           if (value != 0) {
             result += padWithZeros(value, 3);
           }
+        } else {
+          throw "Input string was not in a correct format.";
         }
         break;
       case "g":
         tokenLength = parseRepeatToken(format, cursorPos, "g");
         cursorPos += tokenLength;
-        if (tokenLength <= 2) {
-          result += "A.D.";
-        }
+        result += "A.D.";
         break;
       case "h":
         tokenLength = parseRepeatToken(format, cursorPos, "h");
@@ -170,11 +171,10 @@ function dateToStringWithCustomFormat(date: Date, format: string, utc: boolean)
             result += h1Value ? h1Value : 12;
             break;
           case 2:
+          default:
             const h2Value = hour(localizedDate) % 12;
             result += padWithZeros(h2Value ? h2Value : 12, 2);
             break;
-          default:
-            break;
         }
         break;
       case "H":
@@ -185,9 +185,8 @@ function dateToStringWithCustomFormat(date: Date, format: string, utc: boolean)
             result += hour(localizedDate);
             break;
           case 2:
-            result += padWithZeros(hour(localizedDate), 2);
-            break;
           default:
+            result += padWithZeros(hour(localizedDate), 2);
             break;
         }
         break;
@@ -219,9 +218,8 @@ function dateToStringWithCustomFormat(date: Date, format: string, utc: boolean)
             result += minute(localizedDate);
             break;
           case 2:
-            result += padWithZeros(minute(localizedDate), 2);
-            break;
           default:
+            result += padWithZeros(minute(localizedDate), 2);
             break;
         }
         break;
@@ -239,9 +237,8 @@ function dateToStringWithCustomFormat(date: Date, format: string, utc: boolean)
             result += shortMonths[month(localizedDate) - 1];
             break;
           case 4:
-            result += longMonths[month(localizedDate) - 1];
-            break;
           default:
+            result += longMonths[month(localizedDate) - 1];
             break;
         }
         break;
@@ -253,9 +250,8 @@ function dateToStringWithCustomFormat(date: Date, format: string, utc: boolean)
             result += second(localizedDate);
             break;
           case 2:
-            result += padWithZeros(second(localizedDate), 2);
-            break;
           default:
+            result += padWithZeros(second(localizedDate), 2);
             break;
         }
         break;
@@ -267,9 +263,8 @@ function dateToStringWithCustomFormat(date: Date, format: string, utc: boolean)
             result += localizedDate.getHours() < 12 ? "A" : "P";
             break;
           case 2:
-            result += localizedDate.getHours() < 12 ? "AM" : "PM";
-            break;
           default:
+            result += localizedDate.getHours() < 12 ? "AM" : "PM";
             break;
         }
         break;
@@ -283,16 +278,8 @@ function dateToStringWithCustomFormat(date: Date, format: string, utc: boolean)
           case 2:
             result += padWithZeros(localizedDate.getFullYear() % 100, 2);
             break;
-          case 3:
-            result += padWithZeros(localizedDate.getFullYear(), 3);
-            break;
-          case 4:
-            result += padWithZeros(localizedDate.getFullYear(), 4);
-            break;
-          case 5:
-            result += padWithZeros(localizedDate.getFullYear(), 5);
-            break;
           default:
+            result += padWithZeros(localizedDate.getFullYear(), tokenLength);
             break;
         }
         break;

src/quicktest-py/quicktest.fsx

@@ -11,6 +11,31 @@ let equal expected actual =
     // According the console log arguments are reversed
     Assert.AreEqual(actual, expected)
 
+let throwsError (expected: string) (f: unit -> 'a) : unit =
+    let success =
+        try
+            f () |> ignore
+            true
+        with e ->
+            if not <| String.IsNullOrEmpty(expected) then
+                equal e.Message expected
+
+            false
+    // TODO better error messages
+    equal false success
+
+let throwsAnyError (f: unit -> 'a) : unit =
+    let success =
+        try
+            f () |> ignore
+            true
+        with e ->
+            printfn "Got expected error: %s" e.Message
+            false
+
+    if success then
+        printfn "[ERROR EXPECTED]"
+
 [<EntryPoint>]
 let main argv =
     let name = Array.tryHead argv |> Option.defaultValue "Guest"

tests/Js/Main/DateTimeTests.fs

@@ -1,6 +1,7 @@
 module Fable.Tests.DateTime
 
 open System
+open Util
 open Util.Testing
 open Fable.Tests
 open System.Globalization
@@ -379,6 +380,47 @@ let tests =
         DateTime(2014, 7, 1, 16, 37, 0, DateTimeKind.Utc).ToString("""r \\\zz""", CultureInfo.InvariantCulture)
         |> equal "r \z+0"
 
+        // The tests below are for testing the behaviour when going outside
+        // of the standard token ranges.
+        // For example, the known tokens range for 'H' are "H", "HH", so
+        // we want to test what happens when we do "HHH" or "HHHH" or "HHHHH"
+        // In general, the tests below check what happens when right outside of the known
+        // token ranges and in another exagerated case
+
+        DateTime(2014, 7, 13, 16, 37, 0).ToString("r dddd dddddd", CultureInfo.InvariantCulture)
+        |> equal "r Sunday Sunday"
+
+        throwsAnyError (fun _ ->
+            DateTime(2014, 7, 13, 16, 37, 0).ToString("r ffffffff", CultureInfo.InvariantCulture)
+        )
+
+        throwsAnyError (fun _ ->
+            DateTime(2014, 7, 13, 16, 37, 0).ToString("r FFFFFFFFF", CultureInfo.InvariantCulture)
+        )
+
+        DateTime(2014, 7, 1, 12, 0, 0).ToString("r ggg ggggg", CultureInfo.InvariantCulture)
+        |> equal "r A.D. A.D."
+
+        DateTime(2014, 7, 1, 12, 0, 0).ToString("r hhh hhhhh", CultureInfo.InvariantCulture)
+        |> equal "r 12 12"
+        DateTime(2014, 7, 1, 16, 37, 0).ToString("r HHH HHHHHHHH", CultureInfo.InvariantCulture)
+        |> equal "r 16 16"
+        DateTime(2014, 7, 1, 16, 37, 0).ToString("r KK KKK")
+        |> equal "r  "
+        DateTime(2014, 7, 1, 16, 37, 0).ToString("r mmm mmmm", CultureInfo.InvariantCulture)
+        |> equal "r 37 37"
+        DateTime(2014, 12, 1, 16, 37, 0).ToString("r MMMMM MMMMMMMMM", CultureInfo.InvariantCulture)
+        |> equal "r December December"
+        DateTime(2014, 7, 1, 16, 37, 31).ToString("r sss ssssss", CultureInfo.InvariantCulture)
+        |> equal "r 31 31"
+        DateTime(2014, 7, 1, 16, 37, 0).ToString("r ttt ttttttt", CultureInfo.InvariantCulture)
+        |> equal "r PM PM"
+        DateTime(2019,1,1).ToString("r yyyyyy yyyyyyyyyy", CultureInfo.InvariantCulture)
+        |> equal "r 002019 0000002019"
+
+        // Timezone dependent (test is configured for Europe/Paris timezone)
+        // DateTime(2014, 7, 1, 16, 37, 0).ToString("r zzzz zzzzzz", CultureInfo.InvariantCulture)
+        // |> equal "r +02:00 +02:00"
 
     testCase "DateTime.ToString without separator works" <| fun () -> // See #1131
         DateTime(2017, 9, 5).ToString("yyyyMM")

tests/Python/TestDateTime.fs

@@ -2,6 +2,7 @@ module Fable.Tests.DateTime
 
 open System
 open System.Globalization
+open Util
 open Util.Testing
 open Fable.Tests
 
@@ -402,6 +403,48 @@ let ``test DateTime.ToString with custom format works`` () =
     DateTime(2014, 7, 1, 16, 37, 0, DateTimeKind.Utc).ToString("""r \\\zz""", CultureInfo.InvariantCulture)
     |> equal "r \z+0"
 
+    // The tests below are for testing the behaviour when going outside
+    // of the standard token ranges.
+    // For example, the known tokens range for 'H' are "H", "HH", so
+    // we want to test what happens when we do "HHH" or "HHHH" or "HHHHH"
+    // In general, the tests below check what happens when right outside of the known
+    // token ranges and in another exagerated case
+
+    // DateTime(2014, 7, 13, 16, 37, 0).ToString("r dddd dddddd", CultureInfo.InvariantCulture)
+    // |> equal "r Sunday Sunday"
+
+    // throwsAnyError (fun _ ->
+    //     DateTime(2014, 7, 13, 16, 37, 0).ToString("r ffffffff", CultureInfo.InvariantCulture)
+    // )
+
+    // throwsAnyError (fun _ ->
+    //     DateTime(2014, 7, 13, 16, 37, 0).ToString("r FFFFFFFFF", CultureInfo.InvariantCulture)
+    // )
+
+    // DateTime(2014, 7, 1, 12, 0, 0).ToString("r ggg ggggg", CultureInfo.InvariantCulture)
+    // |> equal "r A.D. A.D."
+
+    // DateTime(2014, 7, 1, 12, 0, 0).ToString("r hhh hhhhh", CultureInfo.InvariantCulture)
+    // |> equal "r 12 12"
+    // DateTime(2014, 7, 1, 16, 37, 0).ToString("r HHH HHHHHHHH", CultureInfo.InvariantCulture)
+    // |> equal "r 16 16"
+    // DateTime(2014, 7, 1, 16, 37, 0).ToString("r KK KKK")
+    // |> equal "r  "
+    // DateTime(2014, 7, 1, 16, 37, 0).ToString("r mmm mmmm", CultureInfo.InvariantCulture)
+    // |> equal "r 37 37"
+    // DateTime(2014, 12, 1, 16, 37, 0).ToString("r MMMMM MMMMMMMMM", CultureInfo.InvariantCulture)
+    // |> equal "r December December"
+    // DateTime(2014, 7, 1, 16, 37, 31).ToString("r sss ssssss", CultureInfo.InvariantCulture)
+    // |> equal "r 31 31"
+    // DateTime(2014, 7, 1, 16, 37, 0).ToString("r ttt ttttttt", CultureInfo.InvariantCulture)
+    // |> equal "r PM PM"
+    // DateTime(2019,1,1).ToString("r yyyyyy yyyyyyyyyy", CultureInfo.InvariantCulture)
+    // |> equal "r 002019 0000002019"
+
+    // Timezone dependent (test is configured for Europe/Paris timezone)
+    // DateTime(2014, 7, 1, 16, 37, 0).ToString("r zzzz zzzzzz", CultureInfo.InvariantCulture)
+    // |> equal "r +02:00 +02:00"
+
 
 [<Fact>]
 let ``test DateTime.ToString without separator works`` () =