将数组合并为一个数组

Question

假设我有以下数组，我如何通过修改给定的 reduce 函数来实现我这个问题中最后一个给定的例子？

我曾尝试将 [cur] 分配给计划键，但它只输出了第一个元素。

我觉得这与我连接对象的方式有关，但我无法自己弄清楚。

{
   employee: 'employee_1',
   customer: {
     name: 'customer_1',
   },
   startdate: '2020-03-01T23:00:00.000Z'
}, {
   employee: 'employee_2',
   customer: {
     name: 'customer_1',
   },
   startdate: '2020-03-01T23:00:00.000Z'
}, {
   employee: 'employee_3',
   customer: {
     name: 'customer_1',
   },
   startdate: '2020-03-01T23:00:00.000Z'
}

plans.reduce(function(o, cur) {

   // Get the index of the key-value pair.
   var occurs = o.reduce(function(n, item, i) {
      return (item.customer.toString() === cur.customer.toString()) ? i : n;
   }, -1);

   // If the name is found,
   if (occurs >= 0) {
      // append the current value to its list of values.
      o[occurs].employee = o[occurs].employee.concat(cur.employee)
      o[occurs].startdate = o[occurs].startdate.concat(cur.startdate)

   // Otherwise
   } else {

      // add the current item to o (but make sure the value is an array).
      var obj = {
         customer: cur.customer,
         employee: [cur.employee],
         startdate: [cur.startdate]
      };
      o = o.concat([obj]);
   }
   return o;
}, [])

这会将给定的数组缩减为如下所示：

{
   customer: {
     name: 'customer_1'
   },
   employee: [{
     employee: 'employee_1'
   }, {
     employee: 'employee_2'
   }, {
     employee: 'employee_3'
   }],
   startdate: [{
     startdate: '2020-03-01T23:00:00.000Z'
   }, {
     startdate: '2020-03-01T23:00:00.000Z'
   }, {
     startdate: '2020-03-01T23:00:00.000Z'
   }]  
}

但我需要的是这样的：

{
   customer: {customer_data},
   plans: [{
     employee: 'employee_1',
     startdate: '2020-03-01T23:00:00.000Z' 
   }, {
     employee: 'employee_2',
     startdate: '2020-03-01T23:00:00.000Z' 
   }, {
     employee: 'employee_3',
     startdate: '2020-03-01T23:00:00.000Z' 
   }]
}

Answer 1

我修改了您的解决方案以获得所需的输出。

您不应使用 reduce，而应使用 find 方法来检查客户是否已存在于数组中。另外你没有考虑计划数组，我已经添加了。

var plans = [
{
   employee: 'employee_1',
   customer: {
     name: 'customer_1',
   },
   startdate: '2020-03-01T23:00:00.000Z'
}, {
   employee: 'employee_2',
   customer: {
     name: 'customer_1',
   },
   startdate: '2020-03-01T23:00:00.000Z'
}, {
   employee: 'employee_3',
   customer: {
     name: 'customer_1',
   },
   startdate: '2020-03-01T23:00:00.000Z'
}
];


var result = plans.reduce(function(o, cur) {

   // Get the index of the key-value pair.
   var occurs = o.find(ob=> ob.customer.name === cur.customer.name);

   // If the name is found,
   if (occurs) {
      // append the current value to its list of values.
      occurs.plans.push( {employee: cur.employee,
          startdate: cur.startdate}  )
   // Otherwise
   } else {

      // add the current item to o (but make sure the value is an array).
      var obj = {
         customer: cur.customer,
         plans:[
          {employee: cur.employee,
          startdate: cur.startdate}
         ]
      };
      o = o.concat(obj);
   }
   return o;
}, [])

console.log(result)

将数组合并为一个数组

Combine arrays to one array

javascript

arrays

reduce

concat