updateWith (Lodash Compatibility)

Use direct assignment instead

This updateWith function operates slowly due to complex path parsing and customizer handling.

Use faster and more modern direct property assignment or optional chaining instead.

Updates the value at the specified path of the object with an updater function, while controlling path creation with a customizer.

const updated = updateWith(obj, path, updater, customizer);

Reference

updateWith(obj, path, updater, customizer?)

Similar to update, but you can control the shape of intermediate objects created when the path doesn't exist using a customizer function.

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

// Basic behavior (same as update)
const object = { a: [{ b: { c: 3 } }] };
updateWith(object, 'a[0].b.c', n => n * n);
// => { a: [{ b: { c: 9 } }] }

// Update with array path
updateWith(object, ['a', 0, 'b', 'c'], n => n + 10);
// => { a: [{ b: { c: 13 } }] }

You can control the shape of intermediate objects created using a customizer.

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

const object = {};

// Use Object constructor as customizer (creates objects instead of arrays)
updateWith(object, '[0][1]', () => 'a', Object);
// => { '0': { '1': 'a' } }
// (default behavior would be { '0': ['a'] })

The customizer receives the value to create, key, and object as arguments.

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

const customizer = (value: any, key: string, object: any) => {
  // Create objects instead of arrays for numeric keys
  if (!isNaN(Number(key))) {
    return {};
  }
};

const result = {};
updateWith(result, '[0][1]', () => 'value', customizer);
// => { '0': { '1': 'value' } }

The customizer is not called if the path already exists.

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

const object = { a: { b: 1 } };
updateWith(
  object,
  'a.b',
  n => n * 2,
  () => {
    console.log('Not called'); // Not called
    return {};
  }
);
// => { a: { b: 2 } }

Parameters

• obj (T): The object to modify.
• path (PropertyKey | readonly PropertyKey[]): The path of the property to update. Can be specified as a string or array.
• updater ((oldValue: any) => any): A function that receives the existing value and returns the new value.
• customizer ((value: any, key: string, object: T) => any, optional): A function that returns the intermediate object to be created when the path doesn't exist. Returns undefined to use default behavior.

Returns

(T): Returns the modified object.