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讯息:19个解决常见JavaScript问题的实用ES6代码段

2022-09-23 09:50:52来源:大前端私房菜


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在我们的开发人员工作流程中,我们经常遇到可能只需要几行代码即可解决的具有挑战性的问题。在本文中,我尝试编写一些有用的代码片段,这些代码片段可以在处理 URL、DOM、事件、日期、用户偏好等时为你提供帮助。

整理学习这些的主要标准就是它的实用性,希望你能从中找到一些有价值的东西,可以应用到你未来的代码库中。

1.如何获取基础 URL?
const getBaseURL = url => url.replace(/[?#].*$/, "");getBaseURL("http://url.com/page?name=Adam&surname=Smith");// "http://url.com/page"
2.如何判断网址是否为绝对网址?
const isAbsoluteURL = str => /^[a-z][a-z0-9+.-]*:/.test(str);isAbsoluteURL("https://google.com"); // trueisAbsoluteURL("ftp://www.myserver.net"); // trueisAbsoluteURL("/foo/bar"); // false
3.如何获取URL参数作为对象?
const getURLParameters = url =>  (url.match(/([^?=&]+)(=([^&]*))/g) || []).reduce(    (a, v) => (      (a[v.slice(0, v.indexOf("="))] = v.slice(v.indexOf("=") + 1)), a    ),    {}  );getURLParameters("google.com"); // {}getURLParameters("http://url.com/page?name=Adam&surname=Smith");// {name: "Adam", surname: "Smith"}
4.如何检查元素是否包含另一个元素?
const elementContains = (parent, child) =>  parent !== child && parent.contains(child);elementContains(  document.querySelector("head"),  document.querySelector("title"));// trueelementContains(document.querySelector("body"), document.querySelector("body"));// false
5.如何获取元素的所有祖先?
const getAncestors = el => {  let ancestors = [];  while (el) {    ancestors.unshift(el);    el = el.parentNode;  }  return ancestors;};getAncestors(document.querySelector("nav"));// [document, html, body, header, nav]
6.如何平滑滚动元素进入视图?
const smoothScroll = element =>  document.querySelector(element).scrollIntoView({    behavior: "smooth"  });smoothScroll("#fooBar"); // scrolls smoothly to the element with the id fooBarsmoothScroll(".fooBar");// scrolls smoothly to the first element with a class of fooBar
7.如何处理元素外的点击?
const onClickOutside = (element, callback) => {  document.addEventListener("click", e => {    if (!element.contains(e.target)) callback();  });};onClickOutside("#my-element", () => console.log("Hello"));// Will log "Hello" whenever the user clicks outside of #my-element
8.如何生成UUID?
const UUIDGeneratorBrowser = () =>  ([1e7] + -1e3 + -4e3 + -8e3 + -1e11).replace(/[018]/g, c =>    (      c ^      (crypto.getRandomValues(new Uint8Array(1))[0] & (15 >> (c / 4)))    ).toString(16)  );UUIDGeneratorBrowser(); // "7982fcfe-5721-4632-bede-6000885be57d"
9.如何获取选中的文本?
const getSelectedText = () => window.getSelection().toString();getSelectedText(); // "Lorem ipsum"
10.如何将文本复制到剪贴板?
const copyToClipboard = str => {  if (navigator && navigator.clipboard && navigator.clipboard.writeText)    return navigator.clipboard.writeText(str);  return Promise.reject("The Clipboard API is not available.");};
11.如何给 HTML 元素添加样式?
const addStyles = (el, styles) => Object.assign(el.style, styles);addStyles(document.getElementById("my-element"), {  background: "red",  color: "#ffff00",  fontSize: "3rem"});
12.如何切换全屏模式?
const fullscreen = (mode = true, el = "body") =>  mode    ? document.querySelector(el).requestFullscreen()    : document.exitFullscreen();fullscreen(); // Opens `body` in fullscreen modefullscreen(false); // Exits fullscreen mode
13.如何检测Caps Lock是否开启?
const el = document.getElementById("password");const msg = document.getElementById("password-message");el.addEventListener("keyup", e => { msg.style = e.getModifierState("CapsLock") ? "display: block" : "display: none";});
14.如何查看日期是否有效?
const isDateValid = (...val) => !Number.isNaN(new Date(...val).valueOf());isDateValid("December 17, 1995 03:24:00"); // trueisDateValid("1995-12-17T03:24:00"); // trueisDateValid("1995-12-17 T03:24:00"); // falseisDateValid("Duck"); // falseisDateValid(1995, 11, 17); // trueisDateValid(1995, 11, 17, "Duck"); // falseisDateValid({}); // false
15.如何从Date中获取冒号时间?
const getColonTimeFromDate = date => date.toTimeString().slice(0, 8);getColonTimeFromDate(new Date()); // "08:38:00"
16.如何从 Date 生成 UNIX 时间戳?
const getTimestamp = (date = new Date()) => Math.floor(date.getTime() / 1000);getTimestamp(); // 1602162242
17、如何查看当前用户的首选语言?
const detectLanguage = (defaultLang = "en-US") =>  navigator.language ||  (Array.isArray(navigator.languages) && navigator.languages[0]) ||  defaultLang;detectLanguage(); // "nl-NL"
18、如何查看用户偏好的配色方案?
const prefersDarkColorScheme = () =>  window &&  window.matchMedia &&  window.matchMedia("(prefers-color-scheme: dark)").matches;prefersDarkColorScheme(); // true
19.如何查看设备是否支持触摸事件?
const supportsTouchEvents = () =>  window && "ontouchstart" in window;supportsTouchEvents(); // true

关键词: 全屏模式 开发人员 是否有效 如何处理 为你提供

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