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Odumosu Matthew
Odumosu Matthew

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Cloning JavaScript Objects: A Comprehensive Guide

JavaScript is known for its reference-based object handling, making object cloning a crucial topic for developers. In this comprehensive guide, we'll explore various techniques to correctly clone JavaScript objects, including both shallow and deep cloning. By the end, you'll have a deep understanding of object cloning in JavaScript.

Introduction to Object Cloning
Before diving into cloning techniques, we'll understand why object cloning is necessary and explore the complexities of object references in JavaScript.

Shallow vs. Deep Cloning
Learn the distinctions between shallow and deep cloning, and find out when each type is appropriate.

Using the Spread Operator (Shallow Cloning)
Explore shallow cloning with examples using the spread operator.

const original = { name: 'John', age: 30 };
const clone = { ...original };

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Using Object.assign() (Shallow Cloning)
Discover how to shallow clone objects with the Object.assign() method.

const original = { name: 'John', age: 30 };
const clone = Object.assign({}, original);

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JSON Methods (Deep Cloning)
Delve into deep cloning using JSON.parse() and JSON.stringify().

const original = { name: 'John', details: { age: 30 } };
const clone = JSON.parse(JSON.stringify(original));

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Lodash Library for Cloning
Learn about the popular lodash library and its clone and cloneDeep functions for cloning objects.

const _ = require('lodash');
const original = { name: 'John', age: 30 };
const clone = _.cloneDeep(original);

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Cloning Arrays of Objects
Handle arrays of objects and ensure they are cloned correctly.

const originalArray = [{ name: 'John' }, { name: 'Jane' }];
const cloneArray = originalArray.map(obj => ({ ...obj }));

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Cloning Built-in Objects
Learn how to clone built-in objects like Date and RegExp.

const originalDate = new Date();
const cloneDate = new Date(originalDate);

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Credit: Graphics sourced from modern javascript blog

Top comments (1)

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jonrandy profile image
Jon Randy 🎖️

You have omitted the powerful built-in structuredClone function.