deep vs shallow copy javascript
Understanding Deep and Shallow Copies in JavaScript
deep vs shallow copy javascript
In JavaScript, a shallow copy creates a new object that is a copy of the original object, but it only duplicates the first level of properties; if a property is a reference to another object, the new object will reference the same inner object instead of creating a copy of it. This means that changes to nested objects in the shallow copy will affect the original object. On the other hand, a deep copy produces a completely independent clone of the original object, including all nested objects, allowing you to modify the deep copy without impacting the original object. While shallow copies can be achieved using `Object.assign()` or the spread operator (`{…obj}`), deep copies typically require more complex techniques, such as using JSON serialization (`JSON.parse(JSON.stringify(obj))`) or utility libraries like Lodash's `_.cloneDeep()`.
To Download Our Brochure: https://www.justacademy.co/download-brochure-for-free
Message us for more information: +91 9987184296
1 - Definition of Shallow Copy: A shallow copy creates a new object which is a duplicate of an existing object but copies only the first level of properties. Nested objects are referenced, not duplicated.
2) Definition of Deep Copy: A deep copy creates a new object and also recursively duplicates all nested objects and their properties, resulting in a completely independent copy.
3) Object Reference: In a shallow copy, nested objects remain linked to the original object. Changes made to nested objects in one will reflect in the other. In contrast, deep copied objects are fully independent.
4) Methods for Shallow Copy: Common methods for creating shallow copies in JavaScript include `Object.assign()`, the spread operator (`…`), and `Array.prototype.slice()`.
5) Methods for Deep Copy: Deep copies can be achieved using JSON methods (`JSON.parse(JSON.stringify(object))`), custom recursive functions, or libraries like Lodash’s `_.cloneDeep()`.
6) Performance: Shallow copies are generally faster to create because they only copy the references of nested objects, while deep copies can be more computationally intensive due to their recursive nature and duplication of every property.
7) Example of Shallow Copy: Given an object `const obj1 = { a: 1, b: { c: 2 } };`, using `const shallowCopy = Object.assign({}, obj1);` results in `shallowCopy.b` pointing to the same object as `obj1.b`.
8) Example of Deep Copy: Using the JSON method, `const deepCopy = JSON.parse(JSON.stringify(obj1));` ensures that `deepCopy.b` is a new object separate from `obj1.b`.
9) Limitations of JSON Method: The JSON method does not work with functions, `undefined`, or special object types like `Date`, `Set`, and `Map`, leading to potential data loss in complex objects.
10) Cyclic References: Shallow copies can handle cyclic references easily, but deep copying requires special handling for such cases, often resulting in errors unless explicitly managed.
11) Data Integrity: When working with data structures that require integrity and immutability (like Redux state), deep copies are preferred to ensure that accidental mutations do not affect the original data.
12) Use Cases for Shallow Copy: Shallow copies are effective when dealing with flat objects or when the original object is not going to be modified, reducing memory footprint.
13) Use Cases for Deep Copy: Complex applications, particularly those involving data manipulation or state management (like in React or Redux), often require deep copies to prevent unintended side effects.
14) Performance Trade offs: When choosing between deep or shallow copies, developers must consider the trade off between speed (shallow) and the need for isolation of nested structures (deep).
15) Practical Implications: Understanding the differences between shallow and deep copies is crucial for debugging in JavaScript, especially in asynchronous environments where object references may lead to unexpected behaviors.
These points cover the fundamental concepts and practical implications of deep vs shallow copying in JavaScript, providing a comprehensive overview suitable for training students.
Browse our course links : https://www.justacademy.co/all-courses
To Join our FREE DEMO Session: Click Here
Contact Us for more info:
- Message us on Whatsapp: +91 9987184296
- Email id: info@justacademy.co