如何使用map函数重新组装下面的json？

Question

我正在尝试从给定的json生成json格式。

我在nodejs中使用了map函数，但它不能正常工作。我在这里给出所有的细节。我想要一个代码，将给我所需的json格式。

给定Json：

var x =
[
[
    {
        "title":"My feel about shape up",
        "answer":"neutral",
        "objectives":[
            "Awareness"
        ]
    },
    {
        "title":"How good is shape up ?",
        "answer":"a",
        "objectives":[
            "Awareness"
        ]
    }
],
[
    {
        "title":"My feel about shape up",
        "answer":"neutral",
        "objectives":[
            "Awareness"
        ]
    },
    {
        "title":"How good is shape up ?",
        "answer":"Awareness",
        "objectives":[
            "Awareness"
        ]
    }
]
];

我尝试过的代码：

result = x.map(function(subarray) {
var data  = subarray.map(v =>{
  const wd= {[v.title ]: v.answer}
   return wd;
   })
   return data;

})

实际输出：

[ [ { 'My feel about shape up': 'neutral' },
{ 'How good is shape up ?': 'a' } ],
[ { 'My feel about shape up': 'neutral' },
{ 'How good is shape up ?': 'Awareness' } ] ]

预期输出：

[ 
{ 'My feel about shape up': 'neutral',
'How good is shape up ?': 'a' } ,
{ 'My feel about shape up': 'neutral',
'How good is shape up ?': 'Awareness' } 
]

Answer 1

您将从内部循环返回一个数组，而不是需要创建一个对象来获得所需的结果，

​

let data = [[{"title":"My feel about shape up","answer":"neutral","objectives":["Awareness"]},{"title":"How good is shape up ?","answer":"a","objectives":["Awareness"]}],[{"title":"My feel about shape up","answer":"neutral","objectives":["Awareness"]},{"title":"How good is shape up ?","answer":"Awareness","objectives":["Awareness"]}]];

let final = data.map(value =>
  value.reduce((op, {title, answer}) => {
    op[title] = answer
    return op
  },{})
)
console.log(final)

​

Answer 2

您可以使用.map()和.reduce()方法来获得所需的输出：

​

const data = [[
    {"title":"My feel about shape up", "answer":"neutral", "objectives":[ "Awareness"]},
    {"title":"How good is shape up ?", "answer":"a", "objectives":[ "Awareness"]}
], [
    {"title":"My feel about shape up", "answer":"neutral", "objectives":["Awareness"]},
    {"title":"How good is shape up ?", "answer":"Awareness", "objectives":["Awareness"]}
]];

const result = data.map(
    arr => arr.reduce((r, {title: k, answer: v}) => (r[k] = v, r), {})
);

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

​

Answer 3

您应该对子数组使用reduce，以便为每个子数组获取一个对象；

​

var x = [[{"title":"My feel about shape up","answer":"neutral","objectives":["Awareness"]},{"title":"How good is shape up ?","answer":"a","objectives":["Awareness"]}],[{"title":"My feel about shape up","answer":"neutral","objectives":["Awareness"]},{"title":"How good is shape up ?","answer":"Awareness","objectives":["Awareness"]}]];
const res = x.map(e => e.reduce((acc, { title, answer }) => ({ ...acc, [title]: answer }), {}));
console.log(res);

​

ES5语法：

​

var x = [[{"title":"My feel about shape up","answer":"neutral","objectives":["Awareness"]},{"title":"How good is shape up ?","answer":"a","objectives":["Awareness"]}],[{"title":"My feel about shape up","answer":"neutral","objectives":["Awareness"]},{"title":"How good is shape up ?","answer":"Awareness","objectives":["Awareness"]}]];
var res = x.map(function(e) {
  return e.reduce(function(acc, curr) {
    return Object.assign({}, acc, { [curr.title]: curr.answer });
  }, {});
});
console.log(res);

​