Question

我想知道是否有一种方法可以基于值将对象动态添加到对象数组中？例如，我有一个对象数组：

[
    {category:A, num:5}, 
    {category:B, num:2}
]

我想创建另一个对象数组，其中对象将是相同的，但是基于num的值重复（因此，类别A为5倍，类别B为2倍）：

[
    {category:A, num:5, repeated:1},
    {category:A, num:5, repeated:2},
    {category:A, num:5, repeated:3},
    {category:A, num:5, repeated:4},
    {category:A, num:5, repeated:5},
    {category:B, num:2, repeated:1}, 
    {category:B, num:2, repeated:2}
]

我尝试了map，forEach，for循环，但是没有任何效果。我对javascript很陌生，有人可以提供帮助！

Answer 1

您可以使用flatMap-

const repeat = ({ num = 0, ...t }) =>
  num === 0
    ? []
    : [ ...repeat({ ...t, num: num - 1 }), { ...t, num, repeated: num } ]

const input = 
  [ { category: "A", num: 5}, { category: "B", num: 2 } ]
  
const output =
  input.flatMap(repeat)
  
console.log(output)

输出-

[
  { category: "A", num: 1, repeated: 1 },
  { category: "A", num: 2, repeated: 2 },
  { category: "A", num: 3, repeated: 3 },
  { category: "A", num: 4, repeated: 4 },
  { category: "A", num: 5, repeated: 5 },
  { category: "B", num: 1, repeated: 1 },
  { category: "B", num: 2, repeated: 2 }
]

Answer 2

您可以结合使用flatMap和map来做到这一点：

var input = [
    {category:"A", num:5}, 
    {category:"B", num:2}
] ;

var result = input.flatMap(e => [...new Array(e.num)].map( (x,i) => ({
    category:e.category,
    num: e.num,
    repeated: i+1
})));
console.log(result);

动态地将对象添加到对象数组

2 个答案: