What is the most efficient way to deep clone an object in JavaScript?
David Y.
—The Problem
What is the most efficient way to deep clone an object in JavaScript?
The Solution
Several methods for deep cloning objects in JavaScript have been invented over the years, with varying efficiency and effectiveness. Modern browsers provide the structuredClone() function, which will create a deep clone of an object provided to it using the structured clone algorithm. A code example:
const person = { firstName: "John", lastName: "Doe", age: 35, purchaseHistory: [ { productName: "apple", quantity: 5, datePurchased: new Date() }, { productName: "banana", quantity: 3, datePurchased: new Date() }, { productName: "pear", quantity: 4, datePurchased: new Date() } ] }; const clone = structuredClone(person); console.assert(clone !== person); // two distinct objects console.assert(clone.firstName === "John"); // same values
Note that structuredClone() does not support object properties that are functions or DOM nodes, and will throw a DataCloneError if these are found in the object provided for cloning.
- YoutubeHow Sentry.io saved me from disaster
- ResourcesImprove Web Browser Performance - Find the JavaScript code causing slowdowns
- SentryJavascript Error Monitoring & Tracing
- ResourcesJavaScript Frontend Error Monitoring 101
- Syntax.fmListen to the Syntax Podcast
- Listen to the Syntax Podcast
![Syntax.fm logo]()
Tasty treats for web developers brought to you by Sentry. Get tips and tricks from Wes Bos and Scott Tolinski.
SEE EPISODES
Considered “not bad” by 4 million developers and more than 100,000 organizations worldwide, Sentry provides code-level observability to many of the world’s best-known companies like Disney, Peloton, Cloudflare, Eventbrite, Slack, Supercell, and Rockstar Games. Each month we process billions of exceptions from the most popular products on the internet.