--- /dev/null
+var $ = require('../internals/export');
+var getBuiltIn = require('../internals/get-built-in');
+var aFunction = require('../internals/a-function');
+var anObject = require('../internals/an-object');
+var isObject = require('../internals/is-object');
+var create = require('../internals/object-create');
+var bind = require('../internals/function-bind');
+var fails = require('../internals/fails');
+
+var nativeConstruct = getBuiltIn('Reflect', 'construct');
+
+// `Reflect.construct` method
+// https://tc39.github.io/ecma262/#sec-reflect.construct
+// MS Edge supports only 2 arguments and argumentsList argument is optional
+// FF Nightly sets third argument as `new.target`, but does not create `this` from it
+var NEW_TARGET_BUG = fails(function () {
+ function F() { /* empty */ }
+ return !(nativeConstruct(function () { /* empty */ }, [], F) instanceof F);
+});
+var ARGS_BUG = !fails(function () {
+ nativeConstruct(function () { /* empty */ });
+});
+var FORCED = NEW_TARGET_BUG || ARGS_BUG;
+
+$({ target: 'Reflect', stat: true, forced: FORCED, sham: FORCED }, {
+ construct: function construct(Target, args /* , newTarget */) {
+ aFunction(Target);
+ anObject(args);
+ var newTarget = arguments.length < 3 ? Target : aFunction(arguments[2]);
+ if (ARGS_BUG && !NEW_TARGET_BUG) return nativeConstruct(Target, args, newTarget);
+ if (Target == newTarget) {
+ // w/o altered newTarget, optimization for 0-4 arguments
+ switch (args.length) {
+ case 0: return new Target();
+ case 1: return new Target(args[0]);
+ case 2: return new Target(args[0], args[1]);
+ case 3: return new Target(args[0], args[1], args[2]);
+ case 4: return new Target(args[0], args[1], args[2], args[3]);
+ }
+ // w/o altered newTarget, lot of arguments case
+ var $args = [null];
+ $args.push.apply($args, args);
+ return new (bind.apply(Target, $args))();
+ }
+ // with altered newTarget, not support built-in constructors
+ var proto = newTarget.prototype;
+ var instance = create(isObject(proto) ? proto : Object.prototype);
+ var result = Function.apply.call(Target, instance, args);
+ return isObject(result) ? result : instance;
+ }
+});