cloneWith (Lodash compatibility)

Implementing custom logic is recommended

This cloneWith function is relatively slow due to complex customizer function processing.

Instead, use clone and implement custom logic directly.

Creates a shallow copy of an object using a customizer function.

const cloned = cloneWith(value, customizer);

Reference

cloneWith(value, customizer?)

Use cloneWith when you want to customize how copying works. The customizer function controls how specific values are copied.

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

// Basic usage (without customizer)
const obj = { a: 1, b: 'hello' };
const cloned = cloneWith(obj);
// Returns: { a: 1, b: 'hello' } (new object instance)

// Transforming number values
const obj2 = { a: 1, b: 2, c: 'text' };
const cloned2 = cloneWith(obj2, value => {
  const obj = {};
  for (const key in value) {
    const val = value[key];
    if (typeof val === 'number') {
      obj[key] = val * 2;
    } else {
      obj[key] = val;
    }
  }
  return obj;
});
// Returns: { a: 2, b: 4, c: 'text' }

// Transforming array elements
const arr = [1, 2, 3];
const clonedArr = cloneWith(arr, value => {
  return value.map(x => x + 10);
});
// Returns: [11, 12, 13]

// Handling specific types
const complex = {
  date: new Date('2023-01-01'),
  number: 42,
  text: 'hello',
};
const clonedComplex = cloneWith(complex, value => {
  const obj = {};
  for (const key in value) {
    const val = value[key];
    if (val instanceof Date) {
      obj[key] = val.toISOString();
    } else if (typeof val === 'string') {
      obj[key] = val.toUpperCase();
    } else {
      obj[key] = val;
    }
  }
  return obj;
});
// Returns: { date: '2023-01-01T00:00:00.000Z', number: 42, text: 'HELLO' }

If the customizer returns undefined, the default copy behavior is used.

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

const obj = { a: 1, b: { c: 2 } };
const cloned = cloneWith(obj, value => {
  // Return undefined for all values = use default copy
  return undefined;
});
// Returns: { a: 1, b: { c: 2 } } (same result as clone)

Parameters

• value (T): The value to clone.
• customizer (function, optional): A function that determines how to copy. In the form (value: any) => any.

Returns

(T): Returns the shallow copy processed by the customizer.