如何在javascript中将数组对象更改为嵌套对象

Question

我想知道如何在 javascript 中将数组对象更改为嵌套对象。我有list数组对象，如何转换为嵌套对象

function nestedobj(arrlist){
  var result ={};
  result.list1 = arrlist[0];
  result.list2 = arrlist[1]
  return list;
}


var list= [
  {id: 1, cn: "SG"},
  {id: 2, cn: "TH"}
]

var list1= [
  {id: 1, cn: "SG"},
  {id: 2, cn: "TH"},
  {id: 3, cn: "MY"}
]

var listobj = this.nestedobj(list);
var listobj1 = this.nestedobj(list1);

console.log(listobj)
console.log(listobj1)

预期产出

{
  "list1":{"id": 1, "cn": "SG"},
  "list2":{"id": 2, "cn": "TH"}
}

{
  "list1":{"id": 1, "cn": "SG"},
  "list2":{"id": 2, "cn": "TH"},
  "list3":{"id": 3, "cn": "MY"}
}

Answer 1

您可以使用Array#reduce方法（或简单循环）生成对象，其中id属性或索引可用于生成属性名称。

var list = [{id: 1,    cn: "SG"  },  {    id: 2,    cn: "TH"  }]

var list1 = [{    id: 1,    cn: "SG"  },  {    id: 2,    cn: "TH"  },  {    id: 3,    cn: "MY"  }]

function convert(arr) {
  // iterate over the array
  return arr.reduce((obj, o, i) => {
    // define the property
    obj[`list${o.id}`] = o; 
    // or with index obj[`list${i + 1}`] = o;
    // return object reference for next call
    return obj;
    // set initial value as empty object to keep the result
  }, {})
}

// or with simple loop
function convert1(arr) {
  const result = {};
  for (let o of arr)
    result[`list${o.id}`] = o;
  return result
}

console.log(convert(list));
console.log(convert(list1));

console.log(convert1(list));
console.log(convert1(list1));