废话不多说，直接拯救直接上。拿用
检查一个元素是盘点否被聚焦
const hasFocus = (ele) => ele === document.activeElement获取一个元素的所有兄弟元素
const siblings = (ele) => .slice.call(ele.parentNode.children).filter((child) => child !== ele);获取选中文本
const getSelectedText = () => window.getSelection().toString();回到上一页
history.back(); // Or history.go(-1);清除所有 cookies
const cookies = document.cookie.split(;).map((item) => item.split(=)).reduce((acc, [k, v]) => (acc[k.trim().replace(", )] = v) && acc, {});将 cookie 转换为对象
const cookies = document.cookie.split(;).map((item) => item.split(=)).reduce((acc, [k, v]) => (acc[k.trim().replace(", )] = v) && acc, {});比较两个数组
// `a` 和 `b` 都是数组 const isEqual = (a, b) => JSON.stringify(a) === JSON.stringify(b); // 或者 const isEqual = (a, b) => a.length === b.length && a.every((v, i) => v === b[i]); // 事例 isEqual([1, 2, 3], [1, 2, 3]); // true isEqual([1, 2, 3], [1, 2, 3]); // false将对象数组转换为单个对象
const toObject = (arr, key) => arr.reduce((a, b) => ({ ...a, [b[key]]: b }), {}); // Or const toObject = (arr, key) => Object.fromEntries(arr.map((it) => [it[key], it])); // 事例 toObject([ { id: 1, name: Alpha, gender: Male }, { id: 2, name: Bravo, gender: Male }, { id: 3, name: Charlie, gender: Female }], id); /* { 1: { id: 1, name: Alpha, gender: Male }, 2: { id: 2, name: Bravo, gender: Male }, 3: { id: 3, name: Charlie, gender: Female } } */根据对象数组的属性进行计数
const countBy = (arr, prop) => arr.reduce((prev, curr) => ((prev[curr[prop]] = ++prev[curr[prop]] || 1), prev), {}); // 事例 countBy([ { branch: audi, model: q8, year: 2019 }, { branch: audi, model: rs7, year: 2020 }, { branch: ford, model: mustang, year: 2019 }, { branch: ford, model: explorer, year: 2020 }, { branch: bmw, model: x7, year: 2020 }, ], branch); // { audi: 2, ford: 2, bmw: 1 }检查数组是否为空
const isNotEmpty = (arr) => Array.isArray(arr) && Object.keys(arr).length > 0; // 事例 isNotEmpty([]); // false isNotEmpty([1, 2, 3]); // true检查多个对象是否相等
const isEqual = (...objects) => objects.every((obj) => JSON.stringify(obj) === JSON.stringify(objects[0])); // 事例 console.log(isEqual({ foo: bar }, { foo: bar })); // true console.log(isEqual({ foo: bar }, { bar: foo })); // false从对象数组中提取指定属性的值
const pluck = (objs, property) => objs.map((obj) => obj[property]); // Example const aa = pluck([ { name: 小智, age: 20 }, { name: 大志, age: 25 }, { name: 王大志, age: 30 }, ], name); // [ 小智, 大志, 王大志 ]反转对象的网站模板键和值
const invert = (obj) => Object.keys(obj).reduce((res, k) => Object.assign(res, { [obj[k]]: k }), {}); // 或 const invert = (obj) => Object.fromEntries(Object.entries(obj).map(([k, v]) => [v, k])); // 事例 invert({ a: 1, b: 2, c: 3 }); // { 1: a, 2: b, 3: c }从对象中删除所有 null 和 undefined 的属性
const removeNullUndefined = (obj) => Object.entries(obj) .reduce((a, [k, v]) => (v == null ? a : ((a[k] = v), a)), {}); // 或 const removeNullUndefined = (obj) => Object.entries(obj) .filter(([_, v]) => v != null) .reduce((acc, [k, v]) => ({ ...acc, [k]: v }), {}); // 或 const removeNullUndefined = (obj) => Object.fromEntries(Object.entries(obj).filter(([_, v]) => v != null)); // 例子 removeNullUndefined({ foo: null, bar: undefined, fuzz: 42} ); // { fuzz: 42 }根据对象的属性对其进行排序
Object.keys(obj) .sort() .reduce((p, c) => ((p[c] = obj[c]), p), {}); // 事例 const colors = { white: #ffffff, black: #000000, red: #ff0000, green: #008000, blue: #0000ff, }; sort(colors); /* { black: #000000, blue: #0000ff, green: #008000, red: #ff0000, white: #ffffff, } */检查一个对象是否是Promise
const isPromise = (obj) => !!obj && (typeof obj === object || typeof obj === function) && typeof obj.then === function;检查一个对象是否是一个数组
const isArray = (obj) => Array.isArray(obj);检查路径是否是相对路径
const isRelative = (path) => !/^([a-z]+:)?[\\/]/i.test(path); // 例子 isRelative(/foo/bar/baz); // false isRelative(C:\\foo\\bar\\baz); // false isRelative(foo/bar/baz.txt); // true isRelative(foo.md); // true将字符串的IT技术网第一个字符改为小写
const lowercaseFirst = (str) => `${str.charAt(0).toLowerCase()}${str.slice(1)}`; // 例子 lowercaseFirst(Hello World); // hello World重复一个字符串
const repeat = (str, numberOfTimes) => str.repeat(numberOfTimes); // 例子 repeat(ab, 3) // ababab给一个小时添加“am/pm”后缀
// `h` is an hour number between 0 and 23 const suffixAmPm = (h) => `${h % 12 === 0 ? 12 : h % 12}${h < 12 ? am : pm}`; // 例子 suffixAmPm(0); // 12am suffixAmPm(5); // 5am suffixAmPm(12); // 12pm suffixAmPm(15); // 3pm suffixAmPm(23); // 11pm计算两个日期之间的不同天数
const diffDays = (date, otherDate) => Math.ceil(Math.abs(date - otherDate) / (1000 * 60 * 60 * 24)); // 例子 diffDays(new Date(2014-12-19), new Date(2020-01-01)); // 1839检查日期是否有效
const isDateValid = (...val) => !Number.isNaN(new Date(...val).valueOf()); isDateValid("December 17, 1995 03:24:00"); // true检查代码是否在Node.js中运行
const isNode = typeof process !== undefined && process.versions != null && process.versions.node != null;检查代码是否在浏览器中运行
const isBrowser = typeof window === object && typeof document === object;将URL参数转换为对象
const getUrlParams = (query) =>Array.from(new URLSearchParams(query)).reduce((p, [k, v]) => Object.assign({}, p, { [k]: p[k] ? (Array.isArray(p[k]) ? p[k] : [p[k]]).concat(v) : v }),{}); // 例子 getUrlParams(location.search); // Get the parameters of the current URL getUrlParams(foo=Foo&bar=Bar); // { foo: "Foo", bar: "Bar" } // Duplicate key getUrlParams(foo=Foo&foo=Fuzz&bar=Bar); // { foo: ["Foo", "Fuzz"], bar: "Bar" }黑暗检测模式
const isDarkMode = window.matchMedia && window.matchMedia((prefers-color-scheme: dark)).matches;拷贝到剪切板
const copyToClipboard = (text) => navigator.clipboard.writeText(text); // 例子 copyToClipboard("Hello World");将RGB转换为十六进制
const rgbToHex = (r, g, b) => "#" + ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1); // 例子 rgbToHex(0, 51, 255); // #0033ff生成一个随机的十六进制颜色
const randomColor = () => `#${Math.random().toString(16).slice(2, 8).padEnd(6, 0)}`; // 或者 const randomColor = () => `#${(~~(Math.random() * (1 << 24))).toString(16)}`;生成随机IP地址
const randomIp = () => Array(4).fill(0) .map((_, i) => Math.floor(Math.random() * 255) + (i === 0 ? 1 : 0)) .join(.); // 例子 randomIp(); // 175.89.174.131使用 Node crypto 模块生成随机字符串
const randomStr = () => require(crypto).randomBytes(32).toString(hex);~~完，我是行代刷碗智，准备去打个点滴，云服务器码网我们下期见!
友摸鱼必作者：Ahmad 译者：前端小智 来源：ishadee
友摸鱼必原文：https://javascript.plainenglish.io/17-life-saving-javascript-one-liners-part1-b0b0b32c9f61 https://javascript.plainenglish.io/another-17-life-saving-javascript-one-liners-8c335bf73d2c
友摸鱼必
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