跳到主要内容

数组

One-Liner​

检查变量是否是数组​

const isArray = Array.isArray(arr);
const isArray = arr instanceof Array;

数字数组的和​

const sum = arr => arr.reduce((a, b) => a + b);

从数组中删除Falsy值​

const removeFalsyValues = arr => arr.filter(x => x);
// or
const removeFalsyValues = arr => arr.filter(Boolean);

数字数组的平均值​

const average = arr => arr.reduce((a, b) => a + b) / arr.length;

合并并删除重复项​

const merge = (arr1, arr2) => [...new Set(arr1.concat(arr2))];
// or
const merge = (arr1, arr2) => [...new Set([...arr1, ...arr2])];

合并两个数组​

const merge = (arr1, arr2) => [].concat(arr1, arr2);
// or
const merge = (arr1, arr2) => [...arr1, ...arr2];

打乱数组​

const shuffle = arr => arr.slice().sort(() => Math.random() - 0.5);

获取数组的最后一个元素​

const lastElement = arr => arr[arr.length - 1];
// or
const lastElement = arr => arr.slice(-1)[0];
// or
const lastElement = arr => arr.slice().pop();

查找数组中的唯一值​

const findUniqueValues = arr =>
  arr.filter(i => arr.indexOf(i) === arr.lastIndexOf(i));

克隆数组​

const clone = arr => arr.slice();
// or
const clone = arr => [...arr];