使用对象数组，我需要更新type为Select (Multiple Answer)的任何对象的计数。
每个type为Select (Multiple Answer)的对象包含一个data对象数组，该数组以逗号分隔value，例如“定价过高，独特，高质量”。这些值应分为自己的对象，并包含在该特定count对象数组的新total和count（所有data值的总和）中。
const arr = [
{
data: [
{count: 7, total: 7, value: "N/A"},
],
name: "item 1",
type: "Yes/No",
}, {
data: [
{count: 5, total: 7, value: "N/A"},
{count: 2, total: 7, value: "Yellow"},
],
name: "item 2",
type: "Select (Single Answer)",
}, {
data: [
{count: 5, total: 7, value: "N/A"},
{count: 1, total: 7, value: "Overpriced,Unique,High quality"},
{count: 1, total: 7, value: "Reliable,High quality"},
],
name: "item 3",
type: "Select (Multiple Answer)",
},
];
预期结果
const result = [
{
data: [
{count: 7, total: 7, value: "N/A"},
],
name: "item 1",
type: "Yes/No",
}, {
data: [
{count: 5, total: 7, value: "N/A"},
{count: 2, total: 7, value: "Yellow"},
],
name: "item 2",
type: "Select (Single Answer)",
}, {
data: [
{count: 5, total: 10, value: "N/A"},
{count: 2, total: 10, value: "High quality"},
{count: 1, total: 10, value: "Overpriced"},
{count: 1, total: 10, value: "Unique"},
{count: 1, total: 10, value: "Reliable"},
],
name: "item 3",
type: "Select (Multiple Answer)",
},
];
我已经开始使用reduce函数，但是它产生的对象与预期结果相差甚远：
当前代码
arr.reduce((a, c) => {
a[c.data.value] = a[c.data.value] || { total: 0 };
a[c.data.value].total += 1;
return a;
}, {})
不希望的结果
{ undefined: { total: 4 } }
答案 0 :(得分：3)
您可以收集这些组并获得total，并附上一个结束符。
它具有total上的闭包并返回一个数组
data: (total => Array.from(
))(0)
通过使用Map以initialValue的形式收集数据
o.data.reduce(
new Map
),
以及使用count，total和value映射新对象的功能。
([value, count]) => ({ count, total, value })
在reduce的回调中，count和value被解构并且值被拆分，以将所有计数转换为映射中收集的所有拆分值。同时，total随实际计数增加。最后，返回地图m。
(m, { count, value }) => (value.split(',').forEach(
v => (m.set(v, (m.get(v) || 0) + count), total+= count)
), m),
var data = [{ data: [{ count: 7, total: 7, value: "N/A" }], name: "item 1", type: "Yes/No" }, { data: [{ count: 5, total: 7, value: "N/A" }, { count: 2, total: 7, value: "Yellow" }], name: "item 2", type: "Select (Single Answer)" }, { data: [{ count: 5, total: 7, value: "N/A" }, { count: 1, total: 7, value: "Overpriced,Unique,High quality" }, { count: 1, total: 7, value: "Reliable,High quality" }], name: "item 3", type: "Select (Multiple Answer)" }],
result = data.map(o => Object.assign({}, o, {
data: (total => Array.from(
o.data.reduce(
(m, { count, value }) => (value.split(',').forEach(
v => (m.set(v, (m.get(v) || 0) + count), total+= count)
), m),
new Map
),
([value, count]) => ({ count, total, value })
))(0)
}));
console.log(result);.as-console-wrapper { max-height: 100% !important; top: 0; }
答案 1 :(得分：1)
这是通过一些注释使其清楚的一种方法：
let arr = [{data:[{count:7,total:7,value:"N/A"}],name:"item 1",type:"Yes/No"},{data:[{count:5,total:7,value:"N/A"},{count:2,total:7,value:"Yellow"}],name:"item 2",type:"Select (Single Answer)"},{data:[{count:5,total:7,value:"N/A"},{count:1,total:7,value:"Overpriced,Unique,High quality"},{count:1,total:7,value:"Reliable,High quality"}],name:"item 3",type:"Select (Multiple Answer)"}];
arr.forEach(x => {
//get all splitted values
const allValues = x.data.filter(y => y.value.split(',').length > 1).reduce((a, e) => a.concat(e.value.split(',')), []);
//remove non-splitten values from data array
x.data = x.data.filter(y => y.value.split(',').length <= 1);
//create new values from old
const newData = allValues.reduce((a, y) => {
const data = a.find(z => z.value === y);
if (data) {
data.count++;
return a;
};
return a.concat({ count: 1, value: y });
}, x.data)
//create new total
const sumCounters = newData.reduce((a, e) => a + e.count, 0);
newData.forEach(e => e.total = sumCounters);
x.data = newData;
return x;
})
console.log(arr);
答案 2 :(得分：0)
自从我开始从事我的工作以来，已经提供了几个很好的答案，但是我不想浪费我的时间，所以这是我的解决方案。
// OP's original array
const arr = [
{
data: [
{count: 7, total: 7, value: "N/A"},
],
name: "item 1",
type: "Yes/No",
}, {
data: [
{count: 5, total: 7, value: "N/A"},
{count: 2, total: 7, value: "Yellow"},
],
name: "item 2",
type: "Select (Single Answer)",
}, {
data: [
{count: 5, total: 7, value: "N/A"},
{count: 1, total: 7, value: "Overpriced,Unique,High quality"},
{count: 1, total: 7, value: "Reliable,High quality"},
],
name: "item 3",
type: "Select (Multiple Answer)",
},
];
arr.forEach(function(select){
// Only modify the multiple answer selects
if(select.type == 'Select (Multiple Answer)'){
var newTotal = 0; // calculate a new total as each item is added to the new array
// use reduce to create a new data array for the multiple answer select
var newDataArray = select.data.reduce(function(acc,d){
valueArr = d['value'].split(','); // get a list of separate value strings
valueArr.forEach(function(valStr){
var unique = true;
// if the new array is empty then go ahead and add the first item
if(acc.length === 0){
acc.push({'count':d.count,'total':d.total,'value':valStr});
newTotal += d.count;
} else {
// check to see if there is already an object with the same value string
// if there is then just update the count and set the unique flag so a new element doesn't get added later
acc.forEach(function(obj){
if(obj['value'] == valStr){
obj['count'] += d.count;
unique = false;
newTotal += d.count;
}
})
if(unique){
acc.push({'count':d.count,'total':d.total,'value':valStr});
newTotal += d.count;
}
}
})
return acc;
}, []);
// Update totals
newDataArray.forEach(function(obj){
obj.total = newTotal;
})
select.data = newDataArray;
}
})
console.log(arr);