Destructuring in JavaScript

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Destructuring in JavaScript is a feature that allows you to extract values from arrays or properties from objects and assign them to variables in a more concise and readable way. It provides a convenient syntax for unpacking values from data structures.

Array Destructuring:

You can extract values from arrays and assign them to variables using square brackets [].

let numbers = [1, 2, 3, 4, 5];

let [first, second] = numbers;
console.log(first);  // Output: 1
console.log(second); // Output: 2

You can also skip elements by using commas without a corresponding variable.

let [first, , third] = numbers;
console.log(first);  // Output: 1
console.log(third);  // Output: 3

Object Destructuring:

You can extract values from objects and assign them to variables using curly braces {}.

let person = { firstName: 'John', lastName: 'Doe' };

let { firstName, lastName } = person;
console.log(firstName); // Output: 'John'
console.log(lastName);  // Output: 'Doe'

You can also assign the extracted values to variables with different names.

let { firstName: fName, lastName: lName } = person;
console.log(fName); // Output: 'John'
console.log(lName); // Output: 'Doe'

Default Values:

You can provide default values for variables in case the value extracted is undefined.

let numbers = [1, 2];

let [first, second, third = 3] = numbers;
console.log(first);  // Output: 1
console.log(second); // Output: 2
console.log(third);  // Output: 3

Nested Destructuring:

You can destructure nested arrays and objects.

let data = {
  person: {
    firstName: 'John',
    lastName: 'Doe',
    age: 30
  }
};

let { person: { firstName, lastName, age } } = data;
console.log(firstName); // Output: 'John'
console.log(lastName);  // Output: 'Doe'
console.log(age);       // Output: 30

Destructuring provides a concise and expressive way to work with arrays and objects in JavaScript, making your code more readable and maintainable. It’s a powerful feature that is commonly used in modern JavaScript development.