javascript - 从每个对象数组中获取最大值

Question

所以我有这样的数据:

data = [
         [{a: "b", value: 12}, {a: "bb", value: 39}, {a: "bb", value: 150}],
         [{a: "c", value: 15}, {a: "cc", value: 83}, {a: "ccc", value: 12}],
         [{a: "d", value: 55}, {a: "dd", value: 9}, {a: "dd", value: 1}]
       ]

我想在每个对象数组中获取最大值。所以结果应该是这样的:

maxValues = [150, 83, 55]

现在我的代码是:

let maxValues = []
let tmp;
let highest = Number.NEGATIVE_INFINITY;

data.map((eachArr, index) => {
  for(let i = eachArr.length -1; i >= 0; i--){
    tmp = eachArr[i].value;
    if(tmp > highest) highest = tmp;
  }
  maxValues.push(highest)
})

结果是

maxValues = [150, 150, 150]

我怎样才能做到这一点？

Answer 1

您可以使用 spread syntax并取映射 value 的最大值.

The spread syntax allows an expression to be expanded in places where multiple arguments (for function calls) or multiple elements (for array literals) or multiple variables  (for destructuring assignment) are expected.

var data = [[{ a: "b", value: 12}, {a: "bb", value: 39 }, {a: "bb", value: 150 }], [{ a: "c", value: 15}, {a: "cc", value: 83 }, {a: "ccc", value: 12 }], [{ a: "d", value: 55}, {a: "dd", value: 9 }, {a: "dd", value: 1 }]],
    result = data.map(a => Math.max(...a.map(b => b.value)));

console.log(result);