Merge pull request nodejs#147 from boingoing/add_napi_is_error

napi: Add napi_is_error API to identify NativeError objects

src/node_jsvmapi.cc

@@ -1462,6 +1462,16 @@ napi_status napi_throw_range_error(napi_env e, const char* msg) {
   return napi_ok;
 }
 
+napi_status napi_is_error(napi_env e, napi_value v, bool* result) {
+  // Omit NAPI_PREAMBLE and GET_RETURN_STATUS because V8 calls here cannot throw JS exceptions.
+  CHECK_ARG(result);
+
+  v8::Local<v8::Value> value = v8impl::V8LocalValueFromJsValue(v);
+  *result = value->IsNativeError();
+
+  return napi_ok;
+}
+
 napi_status napi_get_value_double(napi_env e, napi_value v, double* result) {
   // Omit NAPI_PREAMBLE and GET_RETURN_STATUS because V8 calls here cannot throw JS exceptions.
   CHECK_ARG(result);

src/node_jsvmapi.h

@@ -376,6 +376,7 @@ NODE_EXTERN napi_status napi_throw(napi_env e, napi_value error);
 NODE_EXTERN napi_status napi_throw_error(napi_env e, const char* msg);
 NODE_EXTERN napi_status napi_throw_type_error(napi_env e, const char* msg);
 NODE_EXTERN napi_status napi_throw_range_error(napi_env e, const char* msg);
+NODE_EXTERN napi_status napi_is_error(napi_env e, napi_value v, bool* result);
 
 // Methods to support catching exceptions
 NODE_EXTERN napi_status napi_is_exception_pending(napi_env e, bool* result);

test/addons-abi/test_error/binding.gyp

@@ -0,0 +1,8 @@
+{
+  "targets": [
+    {
+      "target_name": "test_error",
+      "sources": [ "test_error.cc" ]
+    }
+  ]
+}

test/addons-abi/test_error/test.js

@@ -0,0 +1,51 @@
+'use strict';
+
+const common = require('../../common');
+const test_error = require(`./build/${common.buildType}/test_error`);
+const assert = require('assert');
+const theError = new Error('Some error');
+const theTypeError = new TypeError('Some type error');
+const theSyntaxError = new SyntaxError('Some syntax error');
+const theRangeError = new RangeError('Some type error');
+const theReferenceError = new ReferenceError('Some reference error');
+const theURIError = new URIError('Some URI error');
+const theEvalError = new EvalError('Some eval error');
+
+class MyError extends Error { }
+const myError = new MyError('Some MyError');
+
+// Test that native error object is correctly classed
+assert.strictEqual(test_error.checkError(theError), true,
+                   'Error object correctly classed by napi_is_error');
+
+// Test that native type error object is correctly classed
+assert.strictEqual(test_error.checkError(theTypeError), true,
+                   'Type error object correctly classed by napi_is_error');
+
+// Test that native syntax error object is correctly classed
+assert.strictEqual(test_error.checkError(theSyntaxError), true,
+                   'Syntax error object correctly classed by napi_is_error');
+
+// Test that native range error object is correctly classed
+assert.strictEqual(test_error.checkError(theRangeError), true,
+                   'Range error object correctly classed by napi_is_error');
+
+// Test that native URI error object is correctly classed
+assert.strictEqual(test_error.checkError(theURIError), true,
+                   'URI error object correctly classed by napi_is_error');
+
+// Test that native eval error object is correctly classed
+assert.strictEqual(test_error.checkError(theEvalError), true,
+                   'Eval error object correctly classed by napi_is_error');
+
+// Test that class derived from native error is correctly classed
+assert.strictEqual(test_error.checkError(myError), true,
+                   'Class derived from native error correctly classed by napi_is_error');
+
+// Test that non-error object is correctly classed
+assert.strictEqual(test_error.checkError({}), false,
+                   'Non-error object correctly classed by napi_is_error');
+
+// Test that non-error primitive is correctly classed
+assert.strictEqual(test_error.checkError('non-object'), false,
+                   'Non-error primitive correctly classed by napi_is_error');

test/addons-abi/test_error/test_error.cc

@@ -0,0 +1,38 @@
+#include <node_jsvmapi.h>
+
+void checkError(napi_env e, napi_callback_info info) {
+  napi_status status;
+  napi_value jsError;
+
+  status = napi_get_cb_args(e, info, &jsError, 1);
+  if (status != napi_ok) return;
+
+  bool r;
+  status = napi_is_error(e, jsError, &r);
+  if (status != napi_ok) return;
+
+  napi_value result;
+  if (r) {
+      status = napi_get_true(e, &result);
+  } else {
+      status = napi_get_false(e, &result);
+  }
+  if (status != napi_ok) return;
+
+  status = napi_set_return_value(e, info, result);
+  if (status != napi_ok) return;
+}
+
+void Init(napi_env env, napi_value exports, napi_value module) {
+  napi_status status;
+
+  napi_property_descriptor descriptors[] = {
+    { "checkError", checkError }
+  };
+
+  status = napi_define_properties(
+    env, exports, sizeof(descriptors) / sizeof(*descriptors), descriptors);
+  if (status != napi_ok) return;
+}
+
+NODE_MODULE_ABI(addon, Init)