J

Operadores Spread & Rest

JavaScript Syntax Guide

Expandir e coletar valores com operador ...

Operadores Spread & Rest

Expandir e coletar valores com operador ...

JavaScript operadores spread & rest (javascript)
        
          // Spread operator with arrays
const numbers = [1, 2, 3];
const moreNumbers = [...numbers, 4, 5, 6];
console.log(moreNumbers); // [1, 2, 3, 4, 5, 6]

// Copying arrays
const original = [1, 2, 3];
const copy = [...original];
copy.push(4);
console.log(original, copy); // [1, 2, 3], [1, 2, 3, 4]

// Spread with objects
const person = { name: 'John', age: 25 };
const updatedPerson = { ...person, city: 'New York' };
console.log(updatedPerson); // { name: 'John', age: 25, city: 'New York' }

// Merging objects
const obj1 = { a: 1, b: 2 };
const obj2 = { b: 3, c: 4 };
const merged = { ...obj1, ...obj2 };
console.log(merged); // { a: 1, b: 3, c: 4 }

// Rest operator in function parameters
function sum(first, ...rest) {
  return rest.reduce((acc, num) => acc + num, first);
}
console.log(sum(1, 2, 3, 4)); // 10

// Rest in array destructuring
const [first, second, ...remaining] = [1, 2, 3, 4, 5];
console.log(first, second, remaining); // 1, 2, [3, 4, 5]

// Rest in object destructuring
const { a, b, ...others } = { a: 1, b: 2, c: 3, d: 4 };
console.log(a, b, others); // 1, 2, { c: 3, d: 4 }
        
      

Explanation

O operador spread (...) expande iteráveis em elementos individuais, enquanto o operador rest coleta múltiplos elementos em um array ou objeto.

Common Use Cases

  • Manipulação de arrays
  • Mesclagem de objetos
  • Argumentos de função
  • Atualizações imutáveis

Related JavaScript Syntax

Master Operadores Spread & Rest in JavaScript

Understanding Operadores Spread & Rest is fundamental to writing clean and efficient JavaScript code. This comprehensive guide provides you with practical examples and detailed explanations to help you master this important concept.

Whether you're a beginner learning the basics or an experienced developer looking to refresh your knowledge, our examples cover real-world scenarios and best practices for using Operadores Spread & Rest effectively in your JavaScript projects.

Key Takeaways

  • Manipulação de arrays
  • Mesclagem de objetos
  • Argumentos de função