Polyfills就像JavaScript的胶带——快速修复浏览器的漏洞。无论你是自己编写Polyfill还是使用库,它们都是实现向后兼容性的不可或缺的工具。
if(typeofObject.assign!=="function"){Object.assign=function(target,...sources){if(target==null){thrownewTypeError("Cannot convert undefined or null to object");}constto=Object(target);sources.forEach(source=>{if(source!=null){for(constkeyinsource){if(Object.prototype.hasOwnProperty.call(sou...
const array = [1, 2, 3, 4]; function filter(array, callback) { // step #1. same as in map let newArray = []; // step #2. same as in map for(let i = 0; i < array.length; i++) { // difference between map and filter // before pushing to 'newArray' we make sure ...
代码语言:javascript 代码运行次数:0 运行 AI代码解释 Function.prototype.bind = Function.prototype.bind || function(){ var fn = this, presetArgs = [].slice.call(arguments); var context = presetArgs.shift(); return function(){ return fn.apply(context, presetArgs.concat([].slice.call(arguments...
assign || function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; }; var foo = exports.foo = ...
(k in t)) { k++; } if (k >= len) { throw new TypeError('Reduce of empty array with no initial value'); } value = t[k++]; } for (; k < len; k++) { if (k in t) { value = callback(value, t[k], k, t); } } return value; }; }...
好了,以上例子仅用于体现 JavaScript 语法的简单(笑 不过也确实写 try/catch 嵌套写烦了,偶然发现了这个提案,眼前一亮,真的简洁直观🥰 介绍`?=` 运算符 安全赋值运算符 () 提案符旨在简化代码中的错误处理,使代码更易于阅读,特别是在处理可能失败或抛出错误的函数时。当使用运算符时,它会检查函数或操作是否成...
0 - This is a modal window. No compatible source was found for this media. Kickstart YourCareer Get certified by completing the course Get Started Print Page PreviousNext Advertisements
代码语言:javascript 代码运行次数:0 运行 AI代码解释 function mixin(constructor) { return function (...args) { for (let arg of args) { for (let key of Object.getOwnPropertyNames(arg.prototype)) { if (key === 'constructor') continue // 跳过构造函数 Object.defineProperty(constructor.prototype,...
if (predicate.call(thisArg, value, i, list)) return value; } } } 在IE下面有个bug,就是在使用 for in 这种循环的时候,ie下会遍历输出原型链上的方法,比如: 1 2 3 4 5 6 7 8 var a = [1,2]; for(var i in a){ console.log(i); ...