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.
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