语法——原型prototype深入理解

console.log('-----------------------------Object');var obj = {};console.log(obj.__proto__ === Object.prototype);                // trueconsole.log(Object.prototype);                                  // Objectconsole.log(obj.prototype);                                     // undefinedconsole.log('-----------------------------Function');// prototype is a Object property of a Functionvar func = function () {};console.log(func.__proto__ === Function.prototype);             // trueconsole.log(func.prototype === Function.prototype);             // falseconsole.log(func.prototype === Object.prototype);               // falseconsole.log(func.__proto__.__proto__ === Object.prototype);     // trueconsole.log(func.prototype.__proto__ === Object.prototype);     // trueconsole.log('-----------------------------new func');// we look for say from this, then from __proto__ upfunc.say = function () { console.log('func say'); }func.__proto__.say = function () { console.log('func proto say'); }func.prototype.say = function () { console.log('func prototype say'); }// From this, we know that __proto__ is only used as pointer to find parent proto.// And what the newed object has is determined by its prototype, and prototype.__proto__ etc.//func.prototype.__proto__ = func.__proto__;var new_func = new func();new_func.say();func.say();// var new_func = {};// new_func.__proto__ = func.prototype;// func.call(new_func);console.log(new_func.__proto__ === func.prototype);             // trueconsole.log(new_func.prototype);                                // undefined, as it's an Objectfunc.prototype.say = function () { console.log('func prototype say 2'); }new_func.say(); // say 2console.log('-----------------------------derived');var de_func = function () {};de_func.prototype.__proto__ = func.prototype;var new_de = new de_func();new_de.say();// remember:// 1. var x = new obj(); means x.__proto__ = obj.prototype// 2. we look for member from this first, then from this.__proto__