Javascript 如何使用 reduce 从嵌套对象中获取属性值的总和？

Question

我有如下对象：

data_sample = {
  "object_1": {
    "irrelevant_data1": 0,
    "irrelevant_data2": 0,
    "data_needed_to_sum_up": 100,
  },
  "object_a": {
    "irrelevant_data1": 0,
    "irrelevant_data2": 0,
    "irrelevant_data3": 0,
    "data_needed_to_sum_up": 200,
  },
  "object_d": {
    "irrelevant_data1": 0,
    "irrelevant_data2": 0,
    "data_needed_to_sum_up": 300,
  },
}

如何使用reduce方法获取data_sample内所有data_needed_to_sum_up的sum得到预期结果600？

Answer 1

.reduce 适用于数组，您拥有的只是一个对象，但您可以将 .reduce 与 Object.entries 结合使用，如下所示：

data_sample = {
  "object_1": {
    "irrelevant_data1": 0,
    "irrelevant_data2": 0,
    "data_needed_to_sum_up": 100,
  },
  "object_a": {
    "irrelevant_data1": 0,
    "irrelevant_data2": 0,
    "irrelevant_data3": 0,
    "data_needed_to_sum_up": 200,
  },
  "object_d": {
    "irrelevant_data1": 0,
    "irrelevant_data2": 0,
    "data_needed_to_sum_up": 300,
  },
}

console.log(Object.entries(data_sample).reduce((carry, [_, current]) => carry + current.data_needed_to_sum_up, 0))

Answer 2

您可以使用 Array#reduce on Object.values.

let sum = Object.values(data_sample)
         .reduce((acc,cur)=>acc+cur.data_needed_to_sum_up,0);

Answer 3

试试这个：

console.log(Object.values(data_sample).map((x) => x.data_needed_to_sum_up).reduce((x, y) => x + y));

Answer 4

您可以先使用 Object.values 然后再使用 reduce

data_sample = { "object_1": { "irrelevant_data1": 0, "irrelevant_data2": 0, "data_needed_to_sum_up": 100, }, "object_a": { "irrelevant_data1": 0, "irrelevant_data2": 0, "irrelevant_data3": 0, "data_needed_to_sum_up": 200, }, "object_d": { "irrelevant_data1": 0, "irrelevant_data2": 0, "data_needed_to_sum_up": 300, }, }
res = Object.values(data_sample)
    .reduce((acc,curr) => acc = acc + curr["data_needed_to_sum_up"],0)
console.log(res)

Answer 5

先用Object.valuesto再用reduce

Javascript 如何使用 reduce 从嵌套对象中获取属性值的总和？

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