计算 JavaScript 对象中特定值的频率

Question

我有一个 JavaScript 对象，其结构如下：

var subjects = {all: "inactive", firstSingular: "active", secondSingular: "inactive", thirdSingular: "active", firstPlural: "inactive", secondPlural: "inactive", thirdPlural: "inactive"

我想计算此对象中“活动”值的实例数（即 return 2）。我当然可以编写一个函数来遍历对象并对值进行计数，尽管我想知道在 JavaScript 中是否有更简洁的方法（在 1 行中）执行此操作，类似于 collections.Counter 函数在 python.

Answer 1

使用Object#values and Array#reduce：

const subjects = { all: "inactive", firstSingular: "active", secondSingular: "inactive", thirdSingular: "active", firstPlural: "inactive", secondPlural: "inactive", thirdPlural: "inactive" };

const count = Object.values(subjects).reduce((total, value) => value === 'active' ? total + 1 : total, 0);

console.log(count);

另一个使用 Array#filter 而不是 reduce 的解决方案：

const subjects = { all: "inactive", firstSingular: "active", secondSingular: "inactive", thirdSingular: "active", firstPlural: "inactive", secondPlural: "inactive", thirdPlural: "inactive" };

const count = Object.values(subjects).filter(value => value === 'active').length;

console.log(count);

Answer 2

另一种可能的解决方案，使用 filter 并获取结果的长度

var subjects = {all: "inactive", firstSingular: "active",secondSingular:"inactive", thirdSingular: "active", firstPlural: "inactive",secondPlural: "inactive", thirdPlural: "inactive"}

var res = Object.values(subjects).filter((val) => val === 'active').length

console.log(res)

计算 JavaScript 对象中特定值的频率

Count frequency of specific value in JavaScript object

javascript

object

counter

frequency