extend (Lodash Compatibility)

Use Object.assign() instead

This extend function performs slower due to complex logic that handles properties inherited from the prototype chain.

Use the faster and more modern Object.assign() instead.

Copies own and inherited properties from source objects to a target object.

const result = extend(object, source);

Reference

extend(object, ...sources)

Use extend to copy properties from one object to another. Similar to Object.assign(), but also copies inherited properties. This function is an alias of assignIn.

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

// Copy basic properties
const target = { a: 1 };
extend(target, { b: 2 }, { c: 3 });
// Returns: { a: 1, b: 2, c: 3 }

// Also copies inherited properties
function Parent() {
  this.a = 1;
}
Parent.prototype.b = 2;

const source = new Parent();
extend({}, source);
// Returns: { a: 1, b: 2 }

When there are duplicate properties, later source objects overwrite earlier ones.

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

extend({ a: 1, b: 2 }, { b: 3 }, { c: 4 });
// Returns: { a: 1, b: 3, c: 4 }

Parameters

• object (any): The target object to receive properties.
• ...sources (any[]): The source objects that provide properties.

Returns

(any): Returns the object with copied properties. The first argument object is modified.