SOURCE

var FrogPrototype = {
  name: '青蛙',
  legs: 4,
  sayHi: function() {
  	console.log('呱呱呱~ ' + this.name + '有' + this.legs + '条腿');
  }
};

var NormalFrog = function() { };
NormalFrog.prototype = FrogPrototype;

var WeirdFrog = function() { };
WeirdFrog.prototype = Object.assign({ }, FrogPrototype, {
	legs: 8,
  name: '外星青蛙'
});

var frog1 = new NormalFrog();
frog1.sayHi();

var frog2 = new WeirdFrog();
frog2.sayHi();

frog2.legs = 100;
frog2.sayHi();

frog1.sayHi();