defaultsDeep (Lodash Compatibility)

Use destructuring assignment and Object.assign() instead

This defaultsDeep function operates slowly and complexly due to recursive merging of nested objects and circular reference handling.

Use faster, more modern destructuring assignment and Object.assign() instead.

Recursively sets default values on nested objects.

const result = defaultsDeep(target, ...sources);

Reference

defaultsDeep(target, ...sources)

Use defaultsDeep when you want to recursively set default values for undefined properties in nested objects. Similar to defaults, but it also merges nested objects.

import { defaultsDeep } from 'es-toolkit/compat';

// Setting default values in nested objects
defaultsDeep({ a: { b: 2 } }, { a: { b: 3, c: 3 }, d: 4 });
// Returns: { a: { b: 2, c: 3 }, d: 4 }

// Only undefined properties are filled with default values
defaultsDeep({ a: { b: undefined } }, { a: { b: 1 } });
// Returns: { a: { b: 1 } }

// null values are preserved
defaultsDeep({ a: null }, { a: { b: 1 } });
// Returns: { a: null }

You can pass multiple source objects to apply default values in stages.

import { defaultsDeep } from 'es-toolkit/compat';

defaultsDeep({ a: { b: 2 } }, { a: { c: 3 } }, { a: { d: 4 }, e: 5 });
// Returns: { a: { b: 2, c: 3, d: 4 }, e: 5 }

Parameters

• target (any): The target object to set default values on.
• ...sources (any[]): The source objects that provide default values.

Returns

(any): Returns the object with default values recursively set. The first argument target is modified.