feat: add errorWithName (upstream v6.1.0 parity)

.gitignore

@@ -5,3 +5,4 @@
 !/.lua-format
 !/.githooks/
 /output/
+/dist/

changelog.d/20260714_090000_yura_errorwithname.md

@@ -0,0 +1,6 @@
+### Added
+
+- `Effect.Exception.errorWithName` (upstream v6.1.0 parity, #269). Following
+ the fork's string-`Error` model, the name is unobservable: `message`
+ returns the supplied message and `name` keeps answering the constant
+ `"Error"`, the same precedent as `errorWithCause`'s dropped cause.

src/Effect/Exception.js

@@ -12,6 +12,14 @@ export function errorWithCause(msg) {
  };
 }
 
+export function errorWithName(msg) {
+ return function(name) {
+ const e = new Error(msg);
+ e.name = name;
+ return e;
+ };
+}
+
 export function message(e) {
  return e.message;
 }

src/Effect/Exception.lua

@@ -8,6 +8,13 @@ return {
  return msg
  end
  end),
+ errorWithName = (function(msg)
+ return function(_name)
+ -- The name is unobservable through this binding (`name` always answers
+ -- the constant "Error"), so it is dropped like errorWithCause's cause.
+ return msg
+ end
+ end),
  message = (function(err) return err end),
  name = (function(_err)
  -- JS `e.name || "Error"`; the string-Error model carries no name field.

src/Effect/Exception.purs

@@ -6,6 +6,7 @@ module Effect.Exception
  , catchException
  , error
  , errorWithCause
+ , errorWithName
  , message
  , name
  , stack
@@ -35,6 +36,9 @@ foreign import error :: String -> Error
 -- | Create a JavaScript error, specifying a message and a cause
 foreign import errorWithCause :: String -> Error -> Error
 
+-- | Create a JavaScript error, specifying a message and a name
+foreign import errorWithName :: String -> String -> Error
+
 -- | Get the error message from a JavaScript error
 foreign import message :: Error -> String
 

test/regression/exception.lua

@@ -1,6 +1,6 @@
 -- Regression guard for the Lua 5.1 FFI of Effect.Exception.
 --
--- Pins the four semantic fixes:
+-- Pins the semantic fixes:
 -- #81 catchException must RUN the handler Effect (trailing `()`), not return
 -- the unexecuted thunk.
 -- #82 throwException must preserve the message across throw/catch; Lua's
@@ -11,6 +11,10 @@
 -- #84 errorWithCause keeps the message pristine (the cause is unobservable
 -- through this binding — there is no `cause` accessor — so it is dropped
 -- rather than concatenated into the message).
+-- #269 errorWithName was missing from the fork. Upstream takes the message
+-- first and the name second (errorWithName(msg)(name)); the name is
+-- dropped like errorWithCause's cause, so `name` keeps answering the
+-- documented constant "Error".
 --
 -- `Effect a` in this backend is a zero-arg thunk that must be invoked to run.
 -- Run from the repo root: `lua test/regression/exception.lua`.
@@ -87,6 +91,15 @@ end
 -- Sanity: message of a plain error is the message.
 do check("message of a plain error", E.message(E.error("boom")) == "boom", "got " .. tostring(E.message(E.error("boom")))) end
 
+--------------------------------------------------------------------------------
+-- #269 errorWithName keeps the message; the name stays unobservable ----------
+
+do
+ local e = E.errorWithName("boom")("TypeError")
+ check("errorWithName message is the supplied msg", E.message(e) == "boom", "got " .. tostring(E.message(e)))
+ check("errorWithName name stays \"Error\"", E.name(e) == "Error", "got " .. tostring(E.name(e)))
+end
+
 --------------------------------------------------------------------------------
 
 if failures > 0 then error(failures .. " regression check(s) failed") end