erlang.error now throws errors resembling those in Elixir

bryanjos · bryanjos · commit 8d9f3d60a95c · 2017-09-09T09:12:45.000-05:00
diff --git a/src/javascript/lib/core/erlang_compat/erlang.js b/src/javascript/lib/core/erlang_compat/erlang.js
@@ -478,7 +478,19 @@ function _throw(term) {
 }
 
 function error(reason) {
-  throw new ErlangTypes.Tuple(reason, []);
+  if (reason instanceof Map && reason.has(Symbol.for('__exception__'))) {
+    let name = Symbol.keyFor(reason.get(Symbol.for('__struct__')).__MODULE__);
+    name = name
+      .split('.')
+      .slice(1)
+      .join('.');
+    const message = reason.get(Symbol.for('message'));
+    throw new Error(`** (${name}) ${message}`);
+  } else if (is_binary(reason)) {
+    throw new Error(`** (RuntimeError) ${reason}`);
+  } else {
+    throw new Error(`** (ErlangError) Erlang Error ${reason.toString()}`);
+  }
 }
 
 function exit(...args) {
diff --git a/src/javascript/tests/core/erlang_compat/erlang_spec.js b/src/javascript/tests/core/erlang_compat/erlang_spec.js
@@ -132,3 +132,34 @@ test('equals', (t) => {
   t.is(Core.erlang.equals(ref, ref), true);
   t.is(Core.erlang.equals(ref, new Core.Reference()), false);
 });
+
+test('error/1', (t) => {
+  let error = t.throws(() => {
+    Core.erlang.error(
+      new Map([
+        [Symbol.for('__exception__'), true],
+        [Symbol.for('message'), 'hi'],
+        [
+          Symbol.for('__struct__'),
+          {
+            __MODULE__: Symbol.for('Elixir.ArgumentError'),
+          },
+        ],
+      ]),
+    );
+  }, Error);
+
+  t.is(error.message, '** (ArgumentError) hi');
+
+  error = t.throws(() => {
+    Core.erlang.error('hi');
+  }, Error);
+
+  t.is(error.message, '** (RuntimeError) hi');
+
+  error = t.throws(() => {
+    Core.erlang.error(new Core.Tuple('abc', 's'));
+  }, Error);
+
+  t.is(error.message, '** (ErlangError) Erlang Error {abc, s}');
+});
diff --git a/test/support/helpers.ex b/test/support/helpers.ex
@@ -38,6 +38,8 @@ defmodule Helpers do
 
     {out, _a} = System.cmd "node", ["-r", "@std/esm", main_path]
 
+    IO.puts out
+
     out
     |> Poison.decode!
     |> ElixirScript.TermConverter.decode
diff --git a/test/support/integration.ex b/test/support/integration.ex
@@ -7,7 +7,7 @@ defmodule Integration do
 
   def shorthand_failure do
     orders = [%{email: "test@hotmail.com"},%{email: "test2@hotmail.com"}]
-    options = Enum.reduce(orders, [],
+    Enum.reduce(orders, [],
     &(&2 ++ [ [:option, %{value: &1.email}, &1.email] ]))
   end
 
