映射减少对象数组的计数和总和

Question

我有一个对象数组，这些对象具有布尔值属性和一些具有整数值的属性。例如

const arr = [{
    _id: "621bb15de2ecadf024da51d3",
    draw: false,
    pixel: false,
    tooltip: 1,
    points: 1,
    
  },
  {
    _id: "621bb15de2ecadf024da51d8",
    draw: false,
    pixel: true,
    tooltip: 0,
    points: 1,
    
  },
  {
    _id: "621bb15de2ecadf024da51da",
    draw: false,
    pixel: true,
    tooltip: 1,
    points: 1,
    
  },
  {
    _id: "621bb15de2ecadf024da51e5",
    draw: false,
    pixel: true,
    tooltip: 0,
    points: 1,
    
  },
  {
    _id: "621bb15de2ecadf024da51f8",
    draw: false,
    pixel: true,
    tooltip: 1,
    points: 1,
    
  },
  {
    _id: "621bb15ee2ecadf024da5222",
    draw: false,
    pixel: true,
    tooltip: 0,
    points: 1,
    
  },
  {
    _id: "621bb15ee2ecadf024da5230",
    draw: false,
    pixel: true,
    tooltip: 1,
    points: 1,
    
  },
  {
    _id: "621bb15fe2ecadf024da52f3",
    draw: false,
    pixel: false,
    tooltip: 1,
    points: 1,
    
  },
  {
    _id: "621bb160e2ecadf024da5375",
    draw: false,
    pixel: true,
    tooltip: 0,
    points: 1,
  }
]

我正在努力实现 tooltip 和 points 的总和，以及 draw 和 pixel 的计数，它们是真实的。

const res = arr.reduce(function (
          acc,
          curr
        ) {
          return {
            tooltip: acc.tooltip + curr.tooltip,
            points:
              acc.points +
              curr.points,
          };
        });

我得到的输出如下，总和是正确的，

{
  points: 9,
  tooltip: 5
}

但我还想要 draw 和 pixel 的计数，其中它的值为真。

Expected Result:
{
      points: 9,
      tooltip: 5,
      pixel: 7,
      draw: 0
    }

Answer 1

只需使用与 tooltip 和 point 相同的方式，因为在 2 个布尔值之间使用 + 运算符，这些布尔值将被强制转换为整数

const arr = [ { _id: '621bb15de2ecadf024da51d3', draw: false, pixel: false, tooltip: 1, points: 1, }, { _id: '621bb15de2ecadf024da51d8', draw: false, pixel: true, tooltip: 0, points: 1, }, { _id: '621bb15de2ecadf024da51da', draw: false, pixel: true, tooltip: 1, points: 1, }, { _id: '621bb15de2ecadf024da51e5', draw: false, pixel: true, tooltip: 0, points: 1, }, { _id: '621bb15de2ecadf024da51f8', draw: false, pixel: true, tooltip: 1, points: 1, }, { _id: '621bb15ee2ecadf024da5222', draw: false, pixel: true, tooltip: 0, points: 1, }, { _id: '621bb15ee2ecadf024da5230', draw: false, pixel: true, tooltip: 1, points: 1, }, { _id: '621bb15fe2ecadf024da52f3', draw: false, pixel: false, tooltip: 1, points: 1, }, { _id: '621bb160e2ecadf024da5375', draw: false, pixel: true, tooltip: 0, points: 1, }, ]

const res = arr.reduce(function (acc, curr) {
  return {
    tooltip: acc.tooltip + curr.tooltip,
    points: acc.points + curr.points,
    draw: acc.draw + curr.draw,
    pixel: acc.pixel + curr.pixel,
  }
})

console.log(res)

参考资料

12.8.3 The Addition Operator ( + )

Answer 2

你可以试试这个：

let countPixel = 0;
let countDraw = 0;
const res = arr.reduce(function (
    acc,
    curr
  ) {
    if (curr.pixel == true) {
        countPixel++;
    }  
    if (curr.draw == true) {
        countDraw++;
    }
    return {
        tooltip: acc.tooltip + curr.tooltip,
        points: acc.points + curr.points,
        pixel: countPixel,
        draw: countDraw,
    };
});

映射减少对象数组的计数和总和

map reduce count and sum of array of objects

javascript

arrays

mapreduce

参考资料