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如何按多个属性和和组对数组项进行分组?

lodash typescript

Niko Gamulin · 技术社区 · 5 年前

使用下划线,我已经成功地实现了按多个属性对对象进行分组和对组求和的逻辑,但是我还没有找到使用lodash进行分组的方法。

代码如下:

let test = _.chain(response.counterValues)
  .flatten()
  .groupBy(response.counterValues, (item) => {
      return item.duration + '#' + item.timeFrom + '#' + item.timeTo + '#' + item.objectClass;
  })
  .mapValues((value, key) => {
    let sum = _.reduce(value, (memo, val) => {return memo + val.count}, 0);
    let keyItems = key.split('#');
    let duration = keyItems[0];
    let timeFrom = keyItems[1];
    let timeTo = keyItems[2];
    let objectClass = keyItems[3];
    return {duration: duration, timeFrom: timeFrom, timeTo: timeTo, objectClass: objectClass, count: sum};
  }).value();
console.log(test);

这些是示例值:

0: {duration: "h", timeFrom: "1547323200000", timeTo: "1547326800000", objectClass: "car", count: 1}
1: {duration: "h", timeFrom: "1547323200000", timeTo: "1547326800000", objectClass: "car", count: 3}
2: {duration: "h", timeFrom: "1547323200000", timeTo: "1547326800000", objectClass: "car", count: 1}
3: {duration: "h", timeFrom: "1547323200000", timeTo: "1547326800000", objectClass: "car", count: 1}
4: {duration: "h", timeFrom: "1547323200000", timeTo: "1547326800000", objectClass: "car", count: 3}
5: {duration: "h", timeFrom: "1547323200000", timeTo: "1547326800000", objectClass: "car", count: 2}
6: {duration: "h", timeFrom: "1547323200000", timeTo: "1547326800000", objectClass: "car", count: 1}
7: {duration: "h", timeFrom: "1547323200000", timeTo: "1547326800000", objectClass: "car", count: 2}
8: {duration: "h", timeFrom: "1547323200000", timeTo: "1547326800000", objectClass: "car", count: 4}
9: {duration: "h", timeFrom: "1547323200000", timeTo: "1547326800000", objectClass: "car", count: 1}
10: {duration: "h", timeFrom: "1547323200000", timeTo: "1547326800000", objectClass: "car", count: 2}
11: {duration: "h", timeFrom: "1547323200000", timeTo: "1547326800000", objectClass: "car", count: 2}
12: {duration: "h", timeFrom: "1547323200000", timeTo: "1547326800000", objectClass: "car", count: 2}
13: {duration: "h", timeFrom: "1547323200000", timeTo: "1547326800000", objectClass: "car", count: 3}
14: {duration: "h", timeFrom: "1547323200000", timeTo: "1547326800000", objectClass: "car", count: 2}
15: {duration: "h", timeFrom: "1547323200000", timeTo: "1547326800000", objectClass: "car", count: 1}
16: {duration: "h", timeFrom: "1547323200000", timeTo: "1547326800000", objectClass: "car", count: 1}

对于这些对象,我希望得到以下结果:

{duration: "h", timeFrom: 1547323200000, timeTo: 1547326800000, objectClass: "car", count: 32}

是否有人知道如何修改上述代码以获得所需的结果?

1 回复 | 直到 5 年前

edin-m 5 年前

.groupBy(response.counterValues, (item) => { ...

应该是

.groupBy((item) => { ...

因为你用的是uuchain()。