根据时间戳合并 2 个数组及其属性

Question

目前我有一个包含TableRowReading数组的数组，比如let allTableReadings: TableRowReading[][]:

interface TableRowReading {
  time: number; // We can think of the timestamp `time` as the key for the object. 
  sensorValues: SensorValues[];
}

interface SensorValues {
  sensorIndex: number;
  value: number;
}

作为一个示例值，假设我们有：

let allTableReadings: TableRowReading[][] = [
// Array #1
[{  
   time: 1627315260000,
   sensorValues: [{
      sensorIndex: 0, 
      value: 5
   }]
},
{  
   time: 1627314960000,
   sensorValues: [{
      sensorIndex: 0, 
      value: 6
   }]
}],
// Array #2
[{  
   time: 1627315260000,
   sensorValues: [{
      sensorIndex: 1, 
      value: 7
   }]
}],
// Array #3
[{  
   time: 1627315260000,
   sensorValues: [{
      sensorIndex: 2, 
      value: 8
   }]
}]
]

有什么方法可以合并allTableReadings中包含的所有数组，以time为key，同时也合并sensorValues的内容？

let mergedTableReadings: TableRowReading[] = [
{  
   time: 1627315260000,
   sensorValues: [{
      sensorIndex: 0, 
      value: 5
   }, {
      sensorIndex: 1, 
      value: 7
   }, {
      sensorIndex: 2, 
      value: 8
   }]
},
{  
   time: 1627314960000,
   sensorValues: [{
      sensorIndex: 0, 
      value: 6
   }]
}
]

我被困了一段时间，但我认为我无法生成有用的代码示例。我尝试过使用扩展运算符合并并尝试找到一些方便的 lodash 函数，但没有成功。

大致思路如下：

let merged: TableRowReading[] = [];
for (let i = 0; i < allTableReadings.length; i++) {
  // merge allTableReadings[i] into merged
}

Answer 1

使用_.flow() 创建一个函数，该函数将数组的数组展平，按time 分组，然后将每个组映射到所需的形式：

const { flow, flatten, groupBy, map, get, flatMap } = _;

const fn = flow(
  flatten,
  arr => groupBy(arr, 'time'),
  obj => map(obj, group => ({
    time: get(group, '[0].time'),
    sensorValues: flatMap(group, 'sensorValues')
  }))
);

const allTableReadings = [[{ time: 1627315260000, sensorValues: [{ sensorIndex: 0, value: 5 }] }, { time: 1627314960000, sensorValues: [{ sensorIndex: 0, value: 6 }] }],[{ time: 1627315260000, sensorValues: [{ sensorIndex: 1, value: 7 }] }],[{ time: 1627315260000, sensorValues: [{ sensorIndex: 2, value: 8 }] }] ];
   
const result = fn(allTableReadings);

console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.21/lodash.min.js" integrity="sha512-WFN04846sdKMIP5LKNphMaWzU7YpMyCU245etK3g/2ARYbPK9Ub18eG+ljU96qKRCWh+quCY7yefSmlkQw1ANQ==" crossorigin="anonymous" referrerpolicy="no-referrer"></script>

您可以使用 lodash/fp 获得相同想法的简洁版本：

const { flow, flatten, groupBy, map, get, flatMap } = _;

const fn = flow(
  flatten,
  groupBy('time'),
  map(group => ({
    time: get('[0].time', group),
    sensorValues: flatMap('sensorValues', group)
  }))
);

const allTableReadings = [[{ time: 1627315260000, sensorValues: [{ sensorIndex: 0, value: 5 }] }, { time: 1627314960000, sensorValues: [{ sensorIndex: 0, value: 6 }] }],[{ time: 1627315260000, sensorValues: [{ sensorIndex: 1, value: 7 }] }],[{ time: 1627315260000, sensorValues: [{ sensorIndex: 2, value: 8 }] }] ];
   
const result = fn(allTableReadings);

console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.21/lodash.min.js" integrity="sha512-WFN04846sdKMIP5LKNphMaWzU7YpMyCU245etK3g/2ARYbPK9Ub18eG+ljU96qKRCWh+quCY7yefSmlkQw1ANQ==" crossorigin="anonymous" referrerpolicy="no-referrer"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.21/lodash.fp.min.js" integrity="sha512-PQPary7Ah0W8wFgizjGNg0jWpVUKLAxUCvdTNS4lpQFUtoeg5cmSaI8cJK3zh5TDgHDMMHo3tG3ZcLideDlRuQ==" crossorigin="anonymous" referrerpolicy="no-referrer"></script>

Answer 2

检查此代码。

let arr = [{
    time: 1627315260000,
    sensorValues: [{
      sensorIndex: 0,
      value: 5
    }]
  },
  {
    time: 1627314960000,
    sensorValues: [{
      sensorIndex: 0,
      value: 6
    }]
  },
  [{
    time: 1627315260000,
    sensorValues: [{
      sensorIndex: 1,
      value: 7
    }]
  }],
  [{
    time: 1627315260000,
    sensorValues: [{
      sensorIndex: 2,
      value: 8
    }]
  }]
]


arr=arr.flat();

var newArray = [];

for(var i = 0; i< arr.length; i++){
  var idx = newArray.findIndex(x => x.time === arr[i].time);
  if(idx < 0){
    newArray.push(arr[i]);
  } else {
    var newValues = newArray[idx].sensorValues.concat(arr[i].sensorValues);
    newArray[idx].sensorValues = newValues;
  }
}


console.log(newArray)

Answer 3

你可以这样做：

let obj = [[{ time: 1627315260000, sensorValues: [{ sensorIndex: 0, value: 5 }] }, { time: 1627314960000, sensorValues: [{ sensorIndex: 0, value: 6 }] }],[{ time: 1627315260000, sensorValues: [{ sensorIndex: 1, value: 7 }] }],[{ time: 1627315260000, sensorValues: [{ sensorIndex: 2, value: 8 }] }] ];
   

let result = [];

// Array where saved times would be push
let times = []; 
// Flat the array in order toconvert it to a 1D array
obj.flat().forEach(e => {
  // If time isn't saved, push it in the 'times' array and in the 'result' array
  if (!times.includes(e.time)) {
    times.push(e.time);
    result.push({
      time: e.time,
      sensorValues: []
    });
  }
  // Save sensor values
  result[times.indexOf(e.time)].sensorValues.push(...e.sensorValues);
});

console.log(result);