Global / Window

`structuredClone`

Creates a deep clone of a given value using the structured clone algorithm

Syntax

JavaScript

structuredClone(value, options?)

Parameters

Parameter	Type	Description
value	T	The value to be cloned
options	{ transfer?: Transferable[] }	Options with transferable objects

Return Value

A deep clone of the given value

Examples

Basic Usage

const original = { a: 1, b: { c: 2 } };
const clone = structuredClone(original);
clone.b.c = 99;
console.log(original.b.c); // 2 (unchanged)

Practical Example

const data = {
  date: new Date(),
  set: new Set([1, 2, 3]),
  map: new Map([['key', 'value']]),
};
const clone = structuredClone(data);
console.log(clone.date instanceof Date); // true

Advanced Usage

const nested = { a: [{ b: { c: [1, 2, 3] } }] };
const copy = structuredClone(nested);
copy.a[0].b.c.push(4);
console.log(nested.a[0].b.c.length); // 3 (unchanged)

Understanding structuredClone

The structuredClone method in JavaScript creates a deep clone of a given value using the structured clone algorithm. It belongs to the window object and is one of the most widely used methods for working with window values in modern JavaScript and TypeScript applications.

The method signature is structuredClone(value, options?). It accepts 2 parameters: value, options. When called, it returns a deep clone of the given value. Understanding when and how to use structuredClone() helps you write more expressive, readable code.

Common use cases for structuredClone include data transformation, input validation, API response processing, and building reusable utility functions. It works well alongside related methods like object-assign, json-parse, json-stringify, enabling you to chain operations together for complex data manipulation pipelines.

Supported in Chrome 98+, Firefox 94+, Safari 15.4+, Edge 98+, and Node.js 17+.