如何创建新的 object 从另一个 object 数组迭代

Question

const datax = [
        {
          hrCounts: [96, 62, 50, 68, 93, 109, 91, 66, 83, 116, 85, 101],
          hrInCounts: [95, 76, 85, 99, 105, 123, 78, 60, 96, 100, 109, 80],
          hrInTotal: 1106,
          hrLabels: [26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26],
          hrTotal: 10020,
          mo: 5,
          time: "Thu Jun 25 18:30:00 UTC 2020",
        },
        {
          hrCounts: [96, 62, 50, 68, 93, 109, 91, 66, 83, 116, 85, 101],
          hrInCounts: [95, 76, 85, 99, 105, 123, 78, 60, 96, 100, 109, 80],
          hrInTotal: 1106,
          hrLabels: [26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26],
          hrTotal: 10120,
          mo: 5,
          time: "Thu Jun 26 18:30:00 UTC 2020",
        }, {
          hrCounts: [96, 62, 50, 68, 93, 109, 91, 66, 83, 116, 85, 101],
          hrInCounts: [95, 76, 85, 99, 105, 123, 78, 60, 96, 100, 109, 80],
          hrInTotal: 1106,
          hrLabels: [26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26],
          hrTotal: 1020,
          mo: 5,
          time: "Thu Jun 27 18:30:00 UTC 2020",
        },
        {
          hrCounts: [96, 62, 50, 68, 93, 109, 91, 66, 83, 116, 85, 101],
          hrInCounts: [95, 76, 85, 99, 105, 123, 78, 60, 96, 100, 109, 80],
          hrInTotal: 1106,
          hrLabels: [26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26],
          hrTotal: 10110,
          mo: 5,
          time: "Thu Jun 28 18:30:00 UTC 2020",
        }
]

const newArray = datax.foreach((element, index) => {
        const labels = []
        const counts = []
        const idx = index
        labels[idx] = index
        counts[idx] = element.hrTotal
        return {labels, counts}
      });

Trying to achieve below object. I want iterate above array of object and get new array of object with given result below i have tryed using foreach and i am getting error as forach is not a function.

 newArray = [{
               hrTatal:[1020,10110,10120,10020],
               labels:[0,1,2,3]
              }]

Answer 1

Try to use map instead of forEach , like:

const newArray = datax.map((element, index) => {
        const labels = []
        const counts = []
        const idx = index
        labels[idx] = index
        counts[idx] = element.hrTotal
        return {labels, counts}
      });

The reason is because forEach does not return anything ( undefined ). map returns a new modified array.

Answer 2

Use reduce, define the output array inside id and append the needed properties.

 const datax = [{ hrCounts: [96, 62, 50, 68, 93, 109, 91, 66, 83, 116, 85, 101], hrInCounts: [95, 76, 85, 99, 105, 123, 78, 60, 96, 100, 109, 80], hrInTotal: 1106, hrLabels: [26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26], hrTotal: 10020, mo: 5, time: "Thu Jun 25 18:30:00 UTC 2020", }, { hrCounts: [96, 62, 50, 68, 93, 109, 91, 66, 83, 116, 85, 101], hrInCounts: [95, 76, 85, 99, 105, 123, 78, 60, 96, 100, 109, 80], hrInTotal: 1106, hrLabels: [26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26], hrTotal: 10120, mo: 5, time: "Thu Jun 26 18:30:00 UTC 2020", }, { hrCounts: [96, 62, 50, 68, 93, 109, 91, 66, 83, 116, 85, 101], hrInCounts: [95, 76, 85, 99, 105, 123, 78, 60, 96, 100, 109, 80], hrInTotal: 1106, hrLabels: [26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26], hrTotal: 1020, mo: 5, time: "Thu Jun 27 18:30:00 UTC 2020", }, { hrCounts: [96, 62, 50, 68, 93, 109, 91, 66, 83, 116, 85, 101], hrInCounts: [95, 76, 85, 99, 105, 123, 78, 60, 96, 100, 109, 80], hrInTotal: 1106, hrLabels: [26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26], hrTotal: 10110, mo: 5, time: "Thu Jun 28 18:30:00 UTC 2020", } ] const res = datax.reduce((acc, x, i) => { acc[0] = { hrTotal: [...acc[0].hrTotal, x.hrTotal], labels: [...acc[0].labels, i] } return acc; }, [{ hrTotal: [], labels: [] }]) console.log(res)