Issue #2089 - Implement AggregateError

Based-on: m-c 1568903/4,1641355(partial),1652148,1643397

js/src/tests/non262/Error/AggregateError.js

@@ -0,0 +1,82 @@
+// |reftest| skip-if(release_or_beta)
+
+assertEq(typeof AggregateError, "function");
+assertEq(Object.getPrototypeOf(AggregateError), Error);
+assertEq(AggregateError.name, "AggregateError");
+assertEq(AggregateError.length, 2);
+
+assertEq(Object.getPrototypeOf(AggregateError.prototype), Error.prototype);
+assertEq(AggregateError.prototype.name, "AggregateError");
+assertEq(AggregateError.prototype.message, "");
+
+// The |errors| argument is mandatory.
+assertThrowsInstanceOf(() => new AggregateError(), TypeError);
+assertThrowsInstanceOf(() => AggregateError(), TypeError);
+
+// The .errors data property is an array object.
+{
+  let err = new AggregateError([]);
+
+  let {errors} = err;
+  assertEq(Array.isArray(errors), true);
+  assertEq(errors.length, 0);
+
+  // The errors object is modifiable.
+  errors.push(123);
+  assertEq(errors.length, 1);
+  assertEq(errors[0], 123);
+  assertEq(err.errors[0], 123);
+
+  // The property is writable.
+  err.errors = undefined;
+  assertEq(err.errors, undefined);
+}
+
+// The errors argument can be any iterable.
+{
+  function* g() { yield* [1, 2, 3]; }
+
+  let {errors} = new AggregateError(g());
+  assertEqArray(errors, [1, 2, 3]);
+}
+
+// The message property is populated by the second argument.
+{
+  let err;
+
+  err = new AggregateError([]);
+  assertEq(err.message, "");
+
+  err = new AggregateError([], "my message");
+  assertEq(err.message, "my message");
+}
+
+{
+  assertEq("errors" in AggregateError.prototype, false);
+
+  const {
+    configurable,
+    enumerable,
+    value,
+    writable
+  } = Object.getOwnPropertyDescriptor(new AggregateError([]), "errors");
+  assertEq(configurable, true);
+  assertEq(enumerable, false);
+  assertEq(writable, true);
+  assertEq(value.length, 0);
+
+  const g = newGlobal();
+
+  let obj = {};
+  let errors = new g.AggregateError([obj]).errors;
+
+  assertEq(errors.length, 1);
+  assertEq(errors[0], obj);
+
+  // The prototype is |g.Array.prototype| in the cross-compartment case.
+  let proto = Object.getPrototypeOf(errors);
+  assertEq(proto === g.Array.prototype, true);
+}
+
+if (typeof reportCompare === "function")
+  reportCompare(0, 0);