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javascript - 如何在java脚本对象ES5中分组和合并

问题描述

我有一个这样的对象

{
"User 1":[
{"count":"1","stage":"A","jCount":"10","name":"User 1","stageId":"A1"},
{"count":"8","stage":"B","jCount":"10","name":"User 1","stageId":"B1"},
],

"User 2":[
{"count":"7","stage":"C","jCount":"8","name":"User 2","stageId":"C1"},
{"count":"8","stage":"B","jCount":"8","name":"User 2","stageId":"B1"},
{"count":"9","stage":"A","jCount":"8","name":"User 2","stageId":"A1"},
{"count":"8","stage":"D","jCount":"8","name":"User 2","stageId":"D1"},
],

"User 3":[
{"count":"6","stage":"D","jCount":"6","name":"User 3","stageId":"D1"},
{"count":"8","stage":"B","jCount":"6","name":"User 3","stageId":"B1"},
{"count":"1","stage":"A","jCount":"6","name":"User 3","stageId":"A1"},
],
/* Many more users */
}

我正在尝试以这种格式更改我的对象

[
{
"name":"User 1",
"jCount":10,
"stageIdCountA1":1,
"stageIdCountB1":8,
"stageIdCountC1":0,
"stageIdCountD1":0,
},{
"name":"User 2",
"jCount":8,
"stageIdCountA1":9,
"stageIdCountB1":8,
"stageIdCountC1":7,
"stageIdCountD1":8,
},{
"name":"User 3",
"jCount":6,
"stageIdCountA1":1,
"stageIdCountB1":8,
"stageIdCountC1":0,
"stageIdCountD1":6,
},
/* Many more users */
]

最多只有 4 个阶段A1,B1,C1,D1和jCount在子对象的用户数组中很常见

如果没有阶段，它应该打印0

我试图在 angularjs 视图中进行操作，但它变得很困难。

标签： javascriptarraysangularjsjsonobject

解决方案

您可以使用map将每个用户对象映射到数组中的项目，并reduce在 map 函数内部将阶段数组转换为单个对象：

const input={"User 1":[{"count":"1","stage":"A","jCount":"10","name":"User 1","stageId":"A1"},{"count":"8","stage":"B","jCount":"10","name":"User 1","stageId":"B1"},],"User 2":[{"count":"7","stage":"C","jCount":"8","name":"User 2","stageId":"C1"},{"count":"8","stage":"B","jCount":"8","name":"User 2","stageId":"B1"},{"count":"9","stage":"A","jCount":"8","name":"User 2","stageId":"A1"},{"count":"8","stage":"D","jCount":"8","name":"User 2","stageId":"D1"},],"User 3":[{"count":"6","stage":"D","jCount":"6","name":"User 3","stageId":"D1"},{"count":"8","stage":"B","jCount":"6","name":"User 3","stageId":"B1"},{"count":"1","stage":"A","jCount":"6","name":"User 3","stageId":"A1"},],};

const stages = ['A', 'B', 'C', 'D'];
const output = Object.entries(input).map(([name, arr]) => {
  const { jCount } = arr[0];
  const stageCounts = stages.reduce((a, stageName) => {
    const propName = 'stageIdCount' + stageName;
    const foundStage = arr.find(({ stage }) => stageName === stage);
    const count = foundStage ? foundStage.count : 0;
    a[propName] = count;
    return a;
  }, {});
  return { name, jCount, ...stageCounts };
});
console.log(output);

如果你不能使用扩展语法（如果可能的话，你应该将 Babel 集成到你的构建过程中），然后替换

return { name, jCount, ...stageCounts };

和

return Object.assign({ name, jCount }, stageCounts);

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