[runtime] [proxy] implementing [[Get]] trap.

test/mjsunit/harmony/proxies-get.js

+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --harmony-proxies
+
+(function testBasicFunctionality() {
+   var target = {
+     target_one: 1,
+     property: "value"
+   };
+
+   var handler = {handler:1};
+
+   var proxy = new Proxy(target, handler);
+   assertEquals("value", proxy.property);
+   assertEquals(undefined, proxy.nothing);
+   assertEquals(undefined, proxy.handler);
+
+   handler.get = function() { return "value 2" };
+   assertEquals("value 2", proxy.property);
+   assertEquals("value 2", proxy.nothing);
+   assertEquals("value 2", proxy.handler);
+
+   var handler2 = new Proxy({get: function() { return "value 3" }},{});
+   var proxy2 = new Proxy(target, handler2);
+   assertEquals("value 3", proxy2.property);
+   assertEquals("value 3", proxy2.nothing);
+   assertEquals("value 3", proxy2.handler);
+})();
+
+(function testThrowOnGettingTrap() {
+  var handler = new Proxy({}, {get: function(){ throw Error() }});
+  var proxy = new Proxy({}, handler);
+  assertThrows("proxy.property", Error);
+})();
+
+(function testFallback() {
+  var target = {property:"value"};
+  var proxy = new Proxy(target, {});
+  assertEquals("value", proxy.property);
+  assertEquals(undefined, proxy.property2);
+})();
+
+(function testFallbackUndefinedTrap() {
+  var handler = new Proxy({}, {get: function(){ return undefined }});
+  var target = {property:"value"};
+  var proxy = new Proxy(target, handler);
+  assertEquals("value", proxy.property);
+  assertEquals(undefined, proxy.property2);
+})();
+
+(function testFailingInvariant() {
+  var target = {};
+  var handler = { get: function(){ return "value" }}
+  var proxy = new Proxy(target, handler);
+  assertEquals("value", proxy.property);
+  assertEquals("value", proxy.key);
+  assertEquals("value", proxy.key2);
+  assertEquals("value", proxy.key3);
+
+  // Define a non-configurable, non-writeable property on the target for
+  // which the handler will return a different value.
+  Object.defineProperty(target, "key", {
+    configurable: false,
+    writable: false,
+    value: "different value"
+  });
+  assertEquals("value", proxy.property);
+  assertThrows(function(){ proxy.key }, TypeError);
+  assertEquals("value", proxy.key2);
+  assertEquals("value", proxy.key3);
+
+  // Define a non-configurable getter on the target for which the handler
+  // will return a value, according to the spec we do not throw.
+  Object.defineProperty(target, "key2", {
+    configurable: false,
+    get: function() { return "different value" }
+  });
+  assertEquals("value", proxy.property);
+  assertThrows(function(){ proxy.key }, TypeError);
+  assertEquals("value", proxy.key2);
+  assertEquals("value", proxy.key3);
+
+  // Define a non-configurable setter without a corresponding getter on the
+  // target for which the handler will return a value.
+  Object.defineProperty(target, "key3", {
+    configurable: false,
+    set: function() { }
+  });
+  assertEquals("value", proxy.property);
+  assertThrows(function(){ proxy.key }, TypeError);
+  assertEquals("value", proxy.key2);
+  assertThrows(function(){ proxy.key3 }, TypeError);
+})();