javascript根据ES6中的单个项目对象数组合并对象数组

Question

我有以下数据

var data = [
  {username:'andy', entries:[{time_in:12, ..},{time_in:334,...}]},
  {username:'andy2', entries:[{time_in:'sr12', ..},{time_in:334,...}]}
]

期待得到的是最终数据

var result = [
  {username:'andy', entry:12},
  {username:'andy', entry:334},
  {username:'andy2', entry:'sr12'},
  {username:'andy2', entry:334},
]

每个数组对象有更多属性，但为简洁起见，我仅包含用户名

所以我尝试过

data.forEach(item=>{
  item.entries.forEach(entry=>{
    //am stuck here
  })
})

Answer 1

您可以将array#reduce与array#forEach一起使用。遍历每个对象，并针对每个对象遍历entries数组，将新对象添加到累加器中。

const data = [
  {username: 'andy', entries: [{time_in: 12}, {time_in: 334}]},
  {username: 'andy2', entries: [{time_in: 'sr12'}, {time_in: 334}]}
]

const result = data.reduce((r, {username, entries}) => {
  entries.forEach(({time_in: entry}) => r.push({username, entry}))
  return r
}, [])

console.log(result)

Answer 2

您可以执行以下操作：

const final = [];
data.forEach(item =>
  item.entries.forEach(entry =>
    final.push({ username: item.username, entry: entry.time_in })
  )
);

Answer 3

我认为map可以解决问题：

var result = data.map((item) => {
    return {
        username: item.username,
        entries: item.entries.length, // Or whatever processing you want
        ...
    }
}

Answer 4

这是不可变的版本：

const data=[
  {
    username:'andy', entries:[{time_in:12},{time_in:334}]
  }, {
    username:'andy2', entries:[{time_in:'sr12'},{time_in:334}]
  }
];
    

const x = data.reduce((acc, {username, entries}) =>
  acc.concat(
  	entries.map(({time_in}) => ({
        username,
        time_in
    }))
  )
, []);
  
console.log(x);

Answer 5

可能的解决方案：

const result = data.map(({username, entries}) =>
    entries.map(({time_in})=> ({username: username, entry: time_in}))
).reduce((acc, val) => [...acc, ...val], [])