获取浏览器cookie值

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

将RGB转换为16进制

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

复制到剪切板

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

检查日期是否有效

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

找出一年中的某一天（即给出一个日期，程序给出属于本年的第多少天）

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

dayOfYear(new Date());
// Result: 272

将字符串首字母大写

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const capitalize = str =str.charAt(0).toUpperCase() + str.slice(1)

capitalize("follow for more")
// Result: Follow for more

计算两个日期之间相差的天数

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const dayDif = (date1, date2) =Math.ceil(Math.abs(date1.getTime() - date2.getTime()) / 86400000)

dayDif(new Date("2020-10-21"), new Date("2021-10-22"))
// Result: 366

清除所有cookie

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

生成随机16进制

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

console.log(randomHex());
// Result: #92b008

数组去重

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const removeDuplicates = (arr) =[...new Set(arr)];

console.log(removeDuplicates([1, 2, 3, 3, 4, 4, 5, 5, 6]));
// Result: [ 1, 2, 3, 4, 5, 6 ]

从URL中获取查询参数

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

getParameters(window.location)
// Result: { search : "easy", page : 3 }

从日期中获取“时分秒”格式的时间

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const timeFromDate = date =date.toTimeString().slice(0, 8);

console.log(timeFromDate(new Date(2021, 0, 10, 17, 30, 0)));
// Result: "17:30:00"

确认奇偶数

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//通过数据%2来判断并返回布尔类型
const isEven = num =num % 2 === 0;

console.log(isEven(2));
// Result: True

回到顶部（适用于网页右下角快捷返回功能）

//通过将x、y设置为0来实现

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

反转字符串

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const reverse = str =str.split('').reverse().join('');
reverse('hello world');
// Result: 'dlrow olleh'

检查数组是否为空

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//通过对数组长度判断来确定是否为空
const isNotEmpty = arr =Array.isArray(arr) && arr.length 0;

isNotEmpty([1, 2, 3]);
// Result: true

获取用户选定的文本

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

getSelectedText();

打乱数组

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const shuffleArray = (arr) =arr.sort(() =0.5 - Math.random());

console.log(shuffleArray([1, 2, 3, 4]));
// Result: [ 1, 4, 3, 2 ]

检查用户是否处于暗模式

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

console.log(isDarkMode) // Result: True or False