for (key in arr) { if (arrayHasOwnIndex(arr, key)) { console.log(arr[key]); } } for-in 性能 正如上面所说,每次迭代操作会同时搜索实例或者原型属性, for-in 循环的每次迭代都会产生更多开销,因此要比其他循环类型慢,一般速度为其他类型循环的 1/7。因此,除非明确需要迭代一个属性数量未知的对象,...
译者:前端小智 原文:https://medium.com/@jlanne119/10-popular-interview-questions-of-javascript-for-front-end-developers-973c2052892e 为了保证可读性,本文采用意译而非直译 1.如何理解 JS 中的this关键字? JS 初学者总是对this关键字感到困惑,因为与其他现代编程语言相比,JS 中的这this关键字有点棘手。“...
Support for block-level scopes in JavaScript is available viatheletkeyword. Theletkeyword has been widely supported by browsers and back-end JavaScript engines like Node.js for years now.If that’s news to you, it’s worth taking the time to read up onscopes, prototypes, and more. ...
The Merkur is tiny extensible javascript library for front-end microservices(micro frontends). It allows by default server side rendering for loading performance boost. You can connect it with other frameworks or languages because merkur defines easy API. You can use one of six predefined template...
Front-end JavaScript frameworksWhile the number of ways to organize JavaScript is almost infinite, here are some tools that help you build single-page applications. solidjs / solid Star A declarative, efficient, and flexible JavaScript library for building user interfaces....
Basically, in addition to the one that comes with springboot, fastjson is additionally referenced for processing some complex json formats. 2. For the construction of front-end and back-end, you can choose to separate the front-end and back-end, or combine them (in the example, the combina...
enumerable:决定 for in 能否枚举该属性 configurable:决定该属性能否被删除或者改变特征值(包括改为访问器属性)。而且一旦定义为 false,即把属性定义为不可配置的,就不能再把它变回可配置了。 #访问器(getter/setter)属性 访问器属性使得属性在读和写时执行代码,它允许使用者在写和读属性时,得到完全不同的值,它...
JavaScript is free to use for everyone. My Learning Track your progress with the free "My Learning" program here at W3Schools. Log in to your account, and start earning points! This is an optional feature. You can study at W3Schools without using My Learning. ...
A JavaScript framework essentially provides a set pre-written JavaScript code libraries and functions for common front-end development tasks. What is the most used JavaScript framework? React, Angular and Ext JS are among the most used JavaScript frameworks in 2024. Is Django a JavaScript framework...
JSea for JavaScript is the perfect tool for front-end developers who want to improve their interview skills and land their dream job. Download it today and start preparing for your next interview! [ { "feature": "1. JavaScript Tutorial", ...