cloneDeep

Creates a deep copy of the given object.

Signature

function cloneDeep<T>(obj: T): T;

Parameters

obj (T): The object to be copied.

Returns

(T): A deep copy of the given object.

Examples

const num = 29;
const clonedNum = cloneDeep(num);
console.log(clonedNum); // 29
console.log(clonedNum === num); // true

const arr = [1, 2, 3];
const clonedArr = cloneDeep(arr);
console.log(clonedArr); // [1, 2, 3]
console.log(clonedArr === arr); // false

const obj = { a: 1, b: 'es-toolkit', c: [1, 2, 3] };
const clonedObj = cloneDeep(obj);
console.log(clonedObj); // { a: 1, b: 'es-toolkit', c: [1, 2, 3] }
console.log(clonedObj === obj); // false

// Nested objects and arrays
const nestedObj = { a: { b: { c: 'deep' } }, d: [1, 2, { e: 'nested' }] };
const clonedNestedObj = cloneDeep(nestedObj);
console.log(clonedNestedObj); // { a: { b: { c: 'deep' } }, d: [1, 2, { e: 'nested' }] }
console.log(clonedNestedObj === nestedObj); // false
console.log(clonedNestedObj.a === nestedObj.a); // false
console.log(clonedNestedObj.d === nestedObj.d); // false
console.log(clonedNestedObj.d[2] === nestedObj.d[2]); // false

Read-only properties

When you clone an object that has read-only properties defined by getters, the values produced by those getters will be included in the new copied object.

const source = {
  get value() {
    return 3;
  },
};

const cloned = cloneDeep(source);
// cloned is now { value: 3 }

Demo

::: sandpack

import { cloneDeep } from 'es-toolkit/object';

const original = { a: { b: { c: 'deep' } }, d: [1, 2, { e: 'nested' }] };
const cloned = cloneDeep(original);

console.log(cloned);
console.log(original !== cloned);

:::

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