js实用单行代码汇总

获取浏览器Cookie的值

const cookie = name => `; ${document.cookie}`.split(`; ${name}=`).pop().split(';').shift();
    
cookie('_ga');

颜色RGB转十六进制

const rgbToHex = (r, g, b) => "#" + ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1);
    
rgbToHex(0, 51, 255); 

复制到剪贴板

借助navigator.clipboard.writeText可以很容易的讲文本复制到剪贴板

const copyToClipboard = (text) => navigator.clipboard.writeText(text);
    
copyToClipboard("Hello World");

检查日期是否合法

const isDateValid = (...val) => !Number.isNaN(new Date(...val).valueOf());
    
isDateValid("December 17, 1995 03:24:00");

查找日期位于一年中的第几天

const dayOfYear = (date) =>
      Math.floor((date - new Date(date.getFullYear(), 0, 0)) / 1000 / 60 / 60 / 24);
    
dayOfYear(new Date());

英文字符串首字母大写

const capitalize = str => str.charAt(0).toUpperCase() + str.slice(1)
    
capitalize("follow for more")

计算2个日期之间相差多少天

const dayDif = (date1, date2) => Math.ceil(Math.abs(date1.getTime() - date2.getTime()) / 86400000)
    
dayDif(new Date("2020-10-21"), new Date("2021-10-22"))

清除全部Cookie

const clearCookies = document.cookie.split(';').forEach(cookie => document.cookie = cookie.replace(/^ +/, '').replace(/=.*/, `=;expires=${new Date(0).toUTCString()};path=/`));

生成随机十六进制颜色

const randomHex = () => `#${Math.floor(Math.random() * 0xffffff).toString(16).padEnd(6, "0")}`;
    
console.log(randomHex());

数组去重

const removeDuplicates = (arr) => [...new Set(arr)];
    
console.log(removeDuplicates([1, 2, 3, 3, 4, 4, 5, 5, 6]));

从 URL 获取查询参数

const getParameters = (URL) => {
  URL = JSON.parse(
    '{"' +
      decodeURI(URL.split("?")[1])
        .replace(/"/g, '\\"')
        .replace(/&/g, '","')
        .replace(/=/g, '":"') +
      '"}'
  );
  return JSON.stringify(URL);
};

getParameters(window.location);

或者更为简单的：

Object.fromEntries(new URLSearchParams(window.location.search))

时间处理

const timeFromDate = date => date.toTimeString().slice(0, 8);
    
console.log(timeFromDate(new Date(2021, 0, 10, 17, 30, 0))); 

校验数字是奇数还是偶数

const isEven = num => num % 2 === 0;
    
console.log(isEven(2)); 

求数字的平均值

const average = (...args) => args.reduce((a, b) => a + b) / args.length;
    
average(1, 2, 3, 4);

回到顶部

const goToTop = () => window.scrollTo(0, 0);
    
goToTop();

翻转字符串

const reverse = str => str.split('').reverse().join('');
    
reverse('hello world');     

校验数组是否为空

const isNotEmpty = arr => Array.isArray(arr) && arr.length > 0;
    
isNotEmpty([1, 2, 3]);

获取用户选择的文本

const getSelectedText = () => window.getSelection().toString();
    
getSelectedText();

打乱数组

const shuffleArray = (arr) => arr.sort(() => 0.5 - Math.random());
    
console.log(shuffleArray([1, 2, 3, 4]));

检查用户的设备是否处于暗模式

const isDarkMode = window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches
    
console.log(isDarkMode)