Javascript - 如何将数组列表转换为另一个键值数组列表？

Question

所以我已经被这个问题难住了几个小时，我真的想不出一个优雅的解决方案来解决这个问题。假设我有一个这样的数组:

[
   {
     question: "what is your name?",
     answer: "Ben",
     topic: "names"
   },
{
     question: "what is your name?",
     answer: "Ben",
     topic: "names"
   },
   {
     question: "What is dog's name?",
     answer: "Snugglets",
     topic: "names"
   },
   {
     question: "What is your brother's age?",
     answer: 55,
     topic: "ages"
   }
]

我怎样才能把它变成这样的数组？

[
   {
     topic: "names",
     content: [...array of objects based on "names"...]
   },
{
     topic: "ages",
     content: [...array of objects based on "ages"...]
   }
]

我觉得这应该是一件非常容易的事情，但出于某种原因，我的大脑似乎无法理解解决方案。我在这里缺少什么？

更新:感谢所有回复!我没想到会有这么多方法来完成这个。我接受了其中一个答案，因为它与 ES6 相关，而且如果可能的话，我应该明确说明我希望学习 ES6 的实现方式:)

不过，我还必须说，需求也发生了一些变化，而不是预期的数组，就像这样:

[
{
topic: "names",
content: [...array of objects based on "names"...]
},
{
topic: "ages",
content: [...array of objects based on "ages"...]
}
]

数组需要看起来更像这样:

[
{
topic: "names",
content: '<div>
<h3>Question: What is your name?</h3>
<p>Answer: Ben</p>
</div>
<div>
<h3>Question: What is your dog's name?</h3>
<p>Answer: Snugglets</p>
</div>'
},
{
topic: "ages",
content: content: '<div>
<h3>Question: What is your age?</h3>
<p>Answer: 50</p>
</div>
<div>
<h3>Question: What is your brother's age?</h3>
<p>Answer: 52</p>
</div>'
}
]

通常我不喜欢只索取给我的代码，但是当涉及到通过算法转换数据时，我的 Javascript foo 似乎有点弱:( 关于如何将所有这些数组元素合并到一个包含 HTML 的单个字符串，用作每个“主题”的“内容”键？

此外，在 Stackoverflow 上的另一个问题中会更好吗？

Answer 1

您可以将它与一个临时对象分组并使用 Array#forEach 进行迭代.

The forEach() method executes a provided function once per array element.

var data = [{ question: "what is your name?", answer: "Ben", topic: "names" }, { question: "what is your name?", answer: "Ben", topic: "names" }, { question: "What is dog's name?", answer: "Snugglets", topic: "names" }, { question: "What is your brother's age?", answer: 55, topic: "ages" }],
    group = [];

data.forEach(function (a) {
    if (!this[a.topic]) {
        this[a.topic] = { topic: a.topic, content: [] };
        group.push(this[a.topic]);
    }
    this[a.topic].content.push(a);
}, Object.create(null));

console.log(group);