setWith (Lodash Compatibility)

Use direct assignment instead

This setWith function internally calls the updateWith function and operates slowly due to complex path processing and customizer logic.

Use faster and more modern direct assignment or destructuring assignment instead.

Sets a value at the specified path while controlling how objects are created with a customizer function.

const result = setWith(obj, path, value, customizer);

Reference

setWith(object, path, value, customizer)

Use setWith when you want to set a value at a specific path in an object while controlling the type of intermediate objects created with a customizer function. If the customizer returns undefined, the default logic (array for array indices, object otherwise) is used.

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

// Basic usage (no customizer)
const obj1 = {};
setWith(obj1, 'a.b.c', 4);
console.log(obj1);
// Result: { a: { b: { c: 4 } } }

// Customizer forcing array creation
const obj2 = {};
setWith(obj2, '[0][1]', 'value', () => []);
console.log(obj2);
// Result: { '0': [undefined, 'value'] }

// Customize only under specific conditions
const obj3 = {};
setWith(obj3, 'a[0].b.c', 'nested', (value, key) => {
  // Return empty object only for numeric keys (array indices)
  return typeof key === 'string' && /^\d+$/.test(key) ? {} : undefined;
});
console.log(obj3);
// Result: { a: { '0': { b: { c: 'nested' } } } }

// Use Object constructor as customizer
const obj4 = {};
setWith(obj4, 'x[0].y', 42, Object);
console.log(obj4);
// Result: { x: { '0': { y: 42 } } }

// Complex customizer logic
const obj5 = {};
setWith(obj5, 'data.items[0].props.config', 'value', (value, key, object) => {
  console.log('Creating:', key, 'in', object);

  // Use Map for specific keys
  if (key === 'props') {
    return new Map();
  }

  // Array for numeric keys
  if (typeof key === 'string' && /^\d+$/.test(key)) {
    return [];
  }

  // Regular object by default
  return {};
});

// Use WeakMap as intermediate object
const obj6 = {};
setWith(obj6, 'cache.user.profile', 'data', (value, key) => {
  if (key === 'cache') {
    return new WeakMap();
  }
  return undefined; // Use default behavior
});

The customizer function receives three parameters.

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

const obj = {};
setWith(obj, 'a.b[0].c', 'value', (nsValue, key, nsObject) => {
  console.log('nsValue:', nsValue); // Current value (usually undefined)
  console.log('key:', key); // Key to create
  console.log('nsObject:', nsObject); // Parent object

  // Return different object types based on specific conditions
  return key === 'b' ? [] : {};
});

Parameters

• object (T): The object to set the value in.
• path (PropertyPath): The path of the property to set.
• value (any): The value to set.
• customizer ((nsValue: any, key: string, nsObject: T) => any, optional): Function to customize the creation of intermediate objects.

Returns

(T | R): Returns the modified object.