javascript - 数组 'map' 与 'forEach' - 函数式编程

Question

我有一个对象数组:

let reports = [{ inbound_calls: [...], outbound_calls: [...],  outbound_national_calls: [...] },...];

创建新数组并将其分配给变量的最佳方法是什么:

第一种方法 - 一个循环:

let inbound_calls = []; outbound_national_calls = [], outbound_calls = [];

reports.forEach((e) => {
 inbound_calls.push(e.inbound_calls);
 outbound_national_calls.push(e.outbound_national_calls);
 outbound_calls.push(e.outbound_calls);
})

第二种方法:

let inbound_calls = this.reports.map((report) => report.inbound_calls)
let outbound_national_calls = this.reports.map((report) => report.outbound_national_calls)
let outbound_calls = this.reports.map((report) => report.outbound_calls)

我开始学习函数式编程，并想将其应用到我的代码中，我会使用第一种方法(一个循环)，但当我研究函数式编程时，我认为第二种方法是正确的方法(干净得多)但是，我不确定什么是更便宜的操作？

Answer 1

如果您的最终目标是从对象中创建三个变量，则可以按如下方式使用对象解构。不需要循环。

let reports = {
  inbound_calls: [1, 2, 3],
  outbound_calls: [4, 5, 6],
  outbound_national_calls: [7, 8, 9]
};

let {inbound_calls, outbound_calls, outbound_national_calls} = reports;
console.log(inbound_calls);
console.log(outbound_calls);
console.log(outbound_national_calls);