Important features of JavaScript that you must know

In this tutorial, we will learn about the special features of Javascript.

Javascript is a popular programming language. JavaScript is flexible. There are many open source libraries available. GitHub contains a vast amount of Javascript code written by developers around the world. Javascript works great on both front-end and back-end.

The syntax of Javascript is very simple. Without any setup, anyone can execute Javascript programs and make them user-friendly. Javascript can be used by people with basic knowledge of HTML, CSS, and coding.

Characteristics of Javascript

script

Javascript executes client-side scripts in the browser.

Interpreters

The browser interprets JavaScript code.

Event handling

Events are actions. Javascript provides event handling options.

Lightweight

Since Javascript is not a compiled language, the source code is never changed to byte code before running. Due to its lightweight nature, low-end devices can also run Javascript.

case sensitive

In Javascript, names, variables, keywords, and functions are case-sensitive.

Control Statement

Javascript has control statements such as if-else-if, switch case, and loops. Users can write complex code using these control statements.

The subject is a first-class citizen

Javascript arrays, functions and symbols are all objects that can inherit the Object prototype properties. Being a first-class citizen means that the object can complete all tasks.

Support functional programming

Javascript functions can serve as arguments to another function, can be called by reference, and can be assigned to variables.

Dynamic Type

Javascript variables can have any value type. The same variable can have a string value, an integer value, or any other value.

Client verification

Javascript client-side validation allows users to submit valid data to the server during form submission.

Platform independent

Javascript will run the same way in all systems of any operating system.

Asynchronous processing

Javascript async-await and Promise functions provide asynchronous features. Since processes run in parallel, processing time and responsiveness can be improved.

Based on prototype

Javascript follows "Object.prototype" functions instead of class inheritance.

Null value coalescing operator (??)

If the left operand is empty, the null coalescing operator returns the right operand. If the left operand is not "null", the operator returns the value of the left operand. This operator helps avoid Boolean operator errors.

Logical empty assignment (??=)

It is the abbreviation

result=left??right;

Style Console Log

Javascript console can have styles. For example, see the block below.

console.log('%cText %cValue', 'color:black; cursor:pointer', 'color: green;');

The first set of styles applies to the first string with %c, the second %c gets the second set of styles for the second string.

Object abbreviation

Object abbreviation allows users to assign variables and key values ​​​​with the same name, saving space and time.

const name='Egan',
id=1;

//The above snippet can be as follows
const egan={
name,
id
}
console.log(egan);

//Output
{name:'Egan', id:1}

Optional link (?.)

Javascript optional chaining optimizes the regular null check in the example below.

var obj={
   data:{
      id: 1;
   }
}

//General null check
if(obj.data && obj.data.id)

//Optional chaining
obj.data?.id

Lazy/Asynchronous Loading

During HTML parsing, Javascript "delays" and asynchronously downloads files and optimizes page load times. The asynchronous script runs immediately after downloading. Deferred scripts are executed only in Dom order.

Simple client calculation

Javascript can perform simple client-side calculations on the browser.

Large Browser Control

Javascript prioritizes the browser over the server.

Date and time processing

Javascript has built-in functions for getting "date" and time.

HTML content generation

Javascript allows users to add dynamic HTML content when they perform certain actions on the page.

Browser and operating system detection

Javascript has built-in code to detect the browser the user is using.

Let and Const keywords

Javascript replaces the var keyword with the let and const keywords, with block-level scope.

Arrow function

Javascript uses arrow function syntax to help optimize syntax in anonymous functions.

Template text

Javascript allows saving variables as strings and saves development time.

New array function

Javascript array functions enable code optimization. Regular arrays have integer indexes and associative arrays have string indexes.

Default parameters

Javascript uses default parameters to avoid undefined value error conditions.

Attribute abbreviation

Javascript has various shorthand methods, such as .get(), that can save coding time and cost.

Java-like syntax

Javascript syntax is more similar to Java syntax, helping developers work in both programming languages.

If else statement

Javascript "if else" conditional statement performs logical operations.

loop statement

Javascript Loops allow developers to run the same code multiple times using loops.

BigInt

Javascript 允许大整数值。 Javascript 引擎以不同方式支持 BigInt。

动态导入

Javascript动态导入功能允许在运行时添加任何文件。

Promise.allSettled

Javascript Promise.allSettled 方法仅在解决或拒绝所有承诺后才接受承诺数组。

字符串matchAll

Javascript string.matchAll() 返回正则表达式中的所有匹配组。

全局这个

Javascript globalThis 指向全局对象，不考虑窗口对象或自对象。

模块命名空间导出

Javascript模块命名空间导入导出语法如下。

import * as utils from'./utils.mjs';
export {utils}

定义良好的 for-in 顺序

Javascript 'for(a in b)' 在 2020 年之前没有执行顺序。ES2020 给出了规范。

导入.meta

Javascript import.meta 给出脚本标签的元信息。

<script type='module' src='module.js'>
console.log(meta);
//Output
{url: 'file':'//home/user/module.js'}

使用 .at() 进行负索引

Javascript数组索引用数组长度减去过程是一种旧方法。函数.at()可以替代这个任务。

let arr=[10, 20, 30];
arr.at(2);//Prints 20

拥有

Javascript hasOwn 属性是 hasOwnProperty 的扩展。 Javascript hasOwn 是一个静态方法。

let obj = Object.create(null);
obj.hasOwnProperty=function(){};
Object.hasOwnProperty(obj, 'hasOwnProperty');

//Cannot convert the object to the primitive value
Object.hasOwn(obj, 'hasOwnProperty'); //true

类静态块

Javascript 类可以有静态项。

class Color {
   static blue;
   static {
      this.blue = 'blueberry';
   }
}

错误原因

Javascript Error 类还提供错误原因报告。

throw new Error('Error message', { cause: rootCause });

结论

Javascript 具有独特的功能以及面向对象编程和 Java 语言的功能。所讨论的所有功能和其余功能使 Javascript 成为一种强大的编程语言。

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