[js] add externs for the Function class

std/js/Function.hx

@@ -0,0 +1,51 @@
+/*
+ * Copyright (C)2005-2017 Haxe Foundation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+package js;
+
+import haxe.extern.Rest;
+
+@:native("Function")
+extern class Function {
+	/** Specifies the number of arguments expected by the function. **/
+	var length(default,never):Int;
+
+	/** The name of the function. **/
+	var name:String;
+
+	/** Creates a new Function object. **/
+	function new(arg:String, rest:Rest<String>);
+
+	/** Calls a function and sets its this to the provided value, arguments can be passed as an Array object. **/
+	function apply(thisArg:Dynamic, argsArray:Array<Dynamic>):Dynamic;
+
+	/** Calls (executes) a function and sets its this to the provided value, arguments can be passed as they are. **/
+	function call(thisArg:Dynamic, args:Rest<Dynamic>):Dynamic;
+
+	/**
+		Creates a new function which, when called, has its this set to the provided value,
+		with a given sequence of arguments preceding any provided when the new function was called.
+	**/
+	@:pure function bind(thisArg:Dynamic, args:Rest<Dynamic>):Function;
+
+	/** Returns a string representing the source code of the function. **/
+	@:pure function toString():String;
+}