javascript - JSON - 对象数组到数组对象

Question

我有一系列的 JSON 条目:

[{"num": "1","name_A": "Alex" ,"name_B": "Bob"}, {"num": "2","name_A": "Anne" ,"name_B": "Barbra"}]

我试图尽可能轻松地将这个对象数组转换为两个对象 - 一个标题为 name_A，第二个标题为 name_B。对象必须包含标题和一组匹配的数字名称对:

[{title: "name_A", names:[{"1", "Alex}, {"2", "Anne"}]}, {title:"name_B", names: [{"1", "Bob"}, {"2", "Barbra"}]}]

起初我尝试简单地通过减少对象数组两次来创建两个对象，一次用于 name_A，第二次用于 name_B，然后将所有内容粘合在一起:

// get 'names' array
var name_A = objArray.reduce(function(memo, curr) {
    memo.push({curr.num, curr.name_A})
    return memo;
}, []);

但即使这样也是失败的。为什么我用空数组初始化 reduce 就没有 memo 的 push 方法？

第二个问题，我走在正确的轨道上还是有更好的方法来实现这一目标？

Answer 1

内联评论，对预期进行了一些小的修正。

var input = [{ "num": "1", "name_A": "Alex", "name_B": "Bob" }, { "num": "2", "name_A": "Anne", "name_B": "Barbra" }]

var output = input.reduce(function (a, b) {
    // construct new objects and set their properties
    var i = {};
    i[b.num] = b.name_A;
    var j = {};
    j[b.num] = b.name_B;

    // add them to our collection elements
    a[0].names.push(i);
    a[1].names.push(j);

    return a;
   // initializing our collection
}, [{ title: "name_A", names: [] }, { title: "name_B", names: [] }]);

// pretty print our output
console.log(JSON.stringify(output, null, "     "))

var input = [{ "num": "1", "name_A": "Alex", "name_B": "Bob" }, { "num": "2", "name_A": "Anne", "name_B": "Barbra" }]

var output = input.reduce(function (a, b) {
  // construct new objects and set their properties
  var i = {};
  i[b.num] = b.name_A;
  var j = {};
  j[b.num] = b.name_B;

  // add them to our collection elements
  a[0].names.push(i);
  a[1].names.push(j);

  return a;
  // initializing our collection
}, [{ title: "name_A", names: [] }, { title: "name_B", names: [] }]);

so.log(output)

<pre id="output"></pre>
<script>
  var so = {
    log: function(o) {
      document.getElementById("output").innerHTML = JSON.stringify(o, null, "     ")
    }
  }
</script>