默认哈希值 [英] Default hash values

问题描述

我想用 defaults 默认值 params 成员的散列：

  var defaults = {item1：def1，item2：def2}; 
 var params = {item2：param2，item3：param3}; 
 var result = //这里有一些聪明的代码... 
 console.log（result）; // {item1：def1，item2：param2，item3：param3}; 
  

我能想出的最聪明的代码是迭代 defaults 成员，并将它们添加到 params 中（如果它们在那里丢失）。我想知道是否有一些本地解决方案，而不是编写自己的代码？原型设计看起来很有前途，但它只适用于功能对象，我不想在这里。任何想法？如果有人仍然感兴趣：在将近两年后，我想这个问题中提到的巧妙的代码将会是

  __ proto__：Object.create（默认值）
  

查看示例：

  var defaults = {item1：def1，item2 ：def2}; 
 var params = {item2：param2，item3：param3，
 __proto__：Object.create（defaults）}; 
 
 for（var i in params）console.log（i，params [i]）; 
 // item2 param2 
 // item3 param3 
 // item1 def1 
  

请记住 __ proto __ 是不推荐使用，但是与链接建议的 setPrototypeOf（）方法不同。让我们看看未来会是什么。

I'd like to have a hash with params members with defaults default values:

var defaults = { item1: "def1", item2: "def2" };
var params = { item2: "param2", item3: "param3" };
var result = // some clever code here...
console.log(result); // { item1: "def1", item2: "param2", item3: "param3" };

The most clever code I can figure out is to iterate defaults members and add them into params if they are missing there. I wonder if there is some native solution instead of writing own code? Prototyping seems promising, but it only works with functional objects, which I don't want here. Any thoughts?

解决方案

If anyone is still interested: after almost two years, I guess the clever code mentioned in the question would be

__proto__: Object.create(defaults)

See the example:

var defaults = { item1: "def1", item2: "def2" };
var params = { item2: "param2", item3: "param3",
  __proto__: Object.create(defaults) };

for(var i in params) console.log(i,params[i]);
// item2 param2
// item3 param3
// item1 def1

Just keep in mind that the __proto__ is deprecated, however well supported unlike the setPrototypeOf() method suggested by the link. Let's see what the future will be.

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