Home Web Front-end JS Tutorial Comparison between ECMAScript ESand ECMAScript ES6)

Comparison between ECMAScript ESand ECMAScript ES6)

Oct 05, 2024 pm 12:17 PM

Comparación entre ECMAScript ESy ECMAScript ES6)

1. Declaration of Variables

ES5:

  • Use of var to declare variables. It has function as a scope and can give rise to hoisting.

var nombre = 'Maria';


Copy after login

ES6:

  • Introduces let and const that have block as scope, improving security in the handling of variables.

let nombre = 'Maria';  // Variable que puede cambiar
const edad = 30;       // Constante, no puede cambiar


Copy after login

2. Arrow Functions

ES5:

  • Traditional functions require more code and your handling of this can be confusing.

var suma = function(a, b) {
  return a + b;
};


Copy after login

ES6:

  • Arrow functions are more concise and do not change the context of this.

const suma = (a, b) => a + b;


Copy after login

3. Template Strings

ES5:

  • String concatenation is done using the .
  • operator

var saludo = 'Hola ' + nombre + ', tienes ' + edad + ' años.';


Copy after login

ES6:

  • backticks (`) are used to create string templates, allowing interpolation.

const saludo = `Hola ${nombre}, tienes ${edad} años.`;


Copy after login

4. Default Parameters

ES5:

  • There was no support for default parameters, so it was implemented manually.

function saludo(nombre) {
  nombre = nombre || 'Invitado';
  return 'Hola ' + nombre;
}


Copy after login

ES6:

  • The default parameters are declared directly in the function signature.

function saludo(nombre = 'Invitado') {
  return `Hola ${nombre}`;
}


Copy after login

5. Classes

ES5:

  • The concept of classes did not exist. Builder functions and prototypes were used.

function Persona(nombre, edad) {
  this.nombre = nombre;
  this.edad = edad;
}

Persona.prototype.saludar = function() {
  return 'Hola, soy ' + this.nombre;
};


Copy after login

ES6:

  • The classes are introduced, a cleaner syntax closer to other programming languages.

class Persona {
  constructor(nombre, edad) {
    this.nombre = nombre;
    this.edad = edad;
  }

  saludar() {
    return `Hola, soy ${this.nombre}`;
  }
}


Copy after login

6. Modules (Import and Export)

ES5:

  • There was no native support for modules. Libraries such as RequireJS or CommonJS were used.

// CommonJS
var modulo = require('modulo');
module.exports = modulo;


Copy after login

ES6:

  • Introduces native support for modules with import and export.

// Exportar
export const suma = (a, b) => a + b;

// Importar
import { suma } from './modulo';


Copy after login

7. Promises

ES5:

  • There was no native promise handling. Callbacks were relied on to handle asynchrony, leading to problems like "Callback Hell".

function hacerAlgo(callback) {
  setTimeout(function() {
    callback('Hecho');
  }, 1000);
}

hacerAlgo(function(resultado) {
  console.log(resultado);
});


Copy after login

ES6:

  • promises are introduced to handle asynchronous operations more cleanly.

const hacerAlgo = () => {
  return new Promise((resolve, reject) => {
    setTimeout(() => resolve('Hecho'), 1000);
  });
};

hacerAlgo().then(resultado => console.log(resultado));


Copy after login

8. Rest and Spread Operator

ES5:

  • There was no support for easily combining or separating arrays or objects. Techniques such as the use of apply were used.

function sumar(a, b, c) {
  return a + b + c;
}

var numeros = [1, 2, 3];
sumar.apply(null, numeros);


Copy after login

ES6:

  • The rest and spread operators are introduced for easier handling of argument lists and arrays.

// Spread
const numeros = [1, 2, 3];
const resultado = sumar(...numeros);

// Rest
function sumar(...numeros) {
  return numeros.reduce((a, b) => a + b, 0);
}


Copy after login

9. Destructuring

ES5:

  • Extracting values ​​from objects or arrays was manual and error-prone.

var persona = { nombre: 'Maria', edad: 30 };
var nombre = persona.nombre;
var edad = persona.edad;


Copy after login

ES6:

  • destructuring is introduced to extract values ​​from objects and arrays in a cleaner way.

const { nombre, edad } = persona;


Copy after login

Conclusion

ECMAScript 6 (ES6) brings a large number of syntactic and functional improvements that simplify development in JavaScript, making it more readable, maintainable and efficient compared to ECMAScript 5 (ES5).

The above is the detailed content of Comparison between ECMAScript ESand ECMAScript ES6). For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

Hot Topics

Java Tutorial
1662
14
PHP Tutorial
1261
29
C# Tutorial
1234
24
Demystifying JavaScript: What It Does and Why It Matters Demystifying JavaScript: What It Does and Why It Matters Apr 09, 2025 am 12:07 AM

JavaScript is the cornerstone of modern web development, and its main functions include event-driven programming, dynamic content generation and asynchronous programming. 1) Event-driven programming allows web pages to change dynamically according to user operations. 2) Dynamic content generation allows page content to be adjusted according to conditions. 3) Asynchronous programming ensures that the user interface is not blocked. JavaScript is widely used in web interaction, single-page application and server-side development, greatly improving the flexibility of user experience and cross-platform development.

The Evolution of JavaScript: Current Trends and Future Prospects The Evolution of JavaScript: Current Trends and Future Prospects Apr 10, 2025 am 09:33 AM

The latest trends in JavaScript include the rise of TypeScript, the popularity of modern frameworks and libraries, and the application of WebAssembly. Future prospects cover more powerful type systems, the development of server-side JavaScript, the expansion of artificial intelligence and machine learning, and the potential of IoT and edge computing.

JavaScript Engines: Comparing Implementations JavaScript Engines: Comparing Implementations Apr 13, 2025 am 12:05 AM

Different JavaScript engines have different effects when parsing and executing JavaScript code, because the implementation principles and optimization strategies of each engine differ. 1. Lexical analysis: convert source code into lexical unit. 2. Grammar analysis: Generate an abstract syntax tree. 3. Optimization and compilation: Generate machine code through the JIT compiler. 4. Execute: Run the machine code. V8 engine optimizes through instant compilation and hidden class, SpiderMonkey uses a type inference system, resulting in different performance performance on the same code.

JavaScript: Exploring the Versatility of a Web Language JavaScript: Exploring the Versatility of a Web Language Apr 11, 2025 am 12:01 AM

JavaScript is the core language of modern web development and is widely used for its diversity and flexibility. 1) Front-end development: build dynamic web pages and single-page applications through DOM operations and modern frameworks (such as React, Vue.js, Angular). 2) Server-side development: Node.js uses a non-blocking I/O model to handle high concurrency and real-time applications. 3) Mobile and desktop application development: cross-platform development is realized through ReactNative and Electron to improve development efficiency.

How to Build a Multi-Tenant SaaS Application with Next.js (Frontend Integration) How to Build a Multi-Tenant SaaS Application with Next.js (Frontend Integration) Apr 11, 2025 am 08:22 AM

This article demonstrates frontend integration with a backend secured by Permit, building a functional EdTech SaaS application using Next.js. The frontend fetches user permissions to control UI visibility and ensures API requests adhere to role-base

Python vs. JavaScript: The Learning Curve and Ease of Use Python vs. JavaScript: The Learning Curve and Ease of Use Apr 16, 2025 am 12:12 AM

Python is more suitable for beginners, with a smooth learning curve and concise syntax; JavaScript is suitable for front-end development, with a steep learning curve and flexible syntax. 1. Python syntax is intuitive and suitable for data science and back-end development. 2. JavaScript is flexible and widely used in front-end and server-side programming.

From C/C   to JavaScript: How It All Works From C/C to JavaScript: How It All Works Apr 14, 2025 am 12:05 AM

The shift from C/C to JavaScript requires adapting to dynamic typing, garbage collection and asynchronous programming. 1) C/C is a statically typed language that requires manual memory management, while JavaScript is dynamically typed and garbage collection is automatically processed. 2) C/C needs to be compiled into machine code, while JavaScript is an interpreted language. 3) JavaScript introduces concepts such as closures, prototype chains and Promise, which enhances flexibility and asynchronous programming capabilities.

Building a Multi-Tenant SaaS Application with Next.js (Backend Integration) Building a Multi-Tenant SaaS Application with Next.js (Backend Integration) Apr 11, 2025 am 08:23 AM

I built a functional multi-tenant SaaS application (an EdTech app) with your everyday tech tool and you can do the same. First, what’s a multi-tenant SaaS application? Multi-tenant SaaS applications let you serve multiple customers from a sing

See all articles