javascript从新对象中键值对的两级数组中提取id答案

【问题标题】：javascript extract id's from two levels of arrays for key value pairs in new objectjavascript从新对象中键值对的两级数组中提取id
【发布时间】：2018-06-27 20:58:38
【问题描述】：

我正在返回一个有效负载，我需要从有效负载内的两个单独级别中提取 id，并将其作为键值对的单个对象返回。我试图做某种组合或ForEach() 和reduce()，但我似乎找不到正确的方法。这是数据的样子。

{
 orderId:999,
 menuId: 123456,
  questions:[{
    questionId: 123,
    depth: 1,
        answers: [
            { answerId: 999, text: "foo1" },
            { answerId: 888, text: "foo2" }]
  },
  {
    questionId: 654,
    depth: 1,
    answers: [{ answerId: 777, text: "bar" }]
  }]
}

我试图得到的结果

{"q_123": ["999", "888"], "q_654": "777"}

【问题讨论】：

标签： javascript arrays javascript-objects

【解决方案1】：

reduce 的以下方法可以完成这项工作：

const data = {
  orderId: 999,
  menuId: 123456,
  questions: [{
      questionId: 123,
      depth: 1,
      answers: [{
          answerId: 999, 
          text: "foo1"
        }, {
          answerId: 888,
          text: "foo2"
        }
      ]
    }, {
      questionId: 654,
      depth: 1,
      answers: [{
        answerId: 777,
        text: "bar"
      }]
    }
  ]};

const result = data.questions.reduce((all, {
  questionId: id,
  answers
}) => {

  all[`q_${id}`] = answers.map(a => a.answerId);

  return all;
}, {});
console.log(result);

【讨论】：

aww，我没有正确使用 reduce。谢谢，效果很好！

【解决方案2】：

您可以使用reduce 来实现：

const data = {
  orderId: 999, menuId: 123456, questions: [
    {
      questionId: 123,
      depth: 1,
      answers: [
        { answerId: 999, text: "foo1"},
        { answerId: 888, text: "foo2"}
      ]
    },
    {
      questionId: 654,
      depth: 1,
      answers: [ { answerId: 777, text: "bar" }]
    }
  ]
}

const result = data.questions.reduce((acc, {questionId, answers}) => {
  return Object.assign({
    [`q_${questionId}`]: answers.map(
      ({answerId}) => answerId
    )
  }, acc)
}, {});

console.log(result)

【讨论】：

【解决方案3】：

这是简单的JSON parsing。

var input = {
 orderId:999,
 menuId: 123456,
  questions:[{
    questionId: 123,
    depth: 1,
        answers: [
            { answerId: 999, text: "foo1" },
            { answerId: 888, text: "foo2" }]
  },
  {
    questionId: 654,
    depth: 1,
    answers: [{ answerId: 777, text: "bar" }]
  }]
};

var length = input.questions.length;
var questionsobj = input.questions;
var resultJsonData = {};

for(var i=0; i<length; i++) {   
   var question_id = questionsobj[i].questionId;
   var answersobj = questionsobj[i].answers;
   var len = answersobj.length;
   var arrayObject = [];
   
   for(var k=0; k<len; k++) {
      arrayObject[k] = answersobj[k].answerId;
   }
   resultJsonData["q_" + question_id] = arrayObject;
}

console.log(JSON.stringify(resultJsonData));

【讨论】：