javascript definition guide(javascript权威指南)第六章 Example 6-2里一个小错误

javascript definition guide(javascript权威指南)第六章 Example 6-2里的例子有一个小错误

/**
* Copy the enumerable properties of p to o, and return o.
* If o and p have a property by the same name, o's property is overwritten.
* This funcdtion does not handle getters and setters or copy attributes.
*/
function extend(o, p){
	for (prop in p)
		o[prop] = p[prop];
	return o
}

/**
* Return a new object that holds the properties of both o and p.
* If o and p have properties by the same name, the values from o are used
*/
function union(o, p) {
	return extend(extend({}, o), p);
}

这里的union函数实现，如果o和p有相同的属性，o的属性还是会被p中的属性覆盖。

正确的函数应该是：

function union(o, p) {
	return extend(p, extend({}, o));
}