defaultTo (Lodash Compatibility)

Returns the default value for values that are null, undefined, or NaN.

const result = defaultTo(value, defaultValue);

Reference

defaultTo(value, defaultValue)

Use defaultTo when you want to provide a default value when a value is null, undefined, or NaN. It's useful for handling invalid values from API responses or user input.

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

// Basic usage
console.log(defaultTo(null, 'default')); // 'default'
console.log(defaultTo(undefined, 'default')); // 'default'
console.log(defaultTo(NaN, 0)); // 0
console.log(defaultTo('actual', 'default')); // 'actual'
console.log(defaultTo(123, 0)); // 123

Can be used for processing API responses.

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

function processUserData(response) {
  return {
    name: defaultTo(response.name, 'No name'),
    age: defaultTo(response.age, 0),
    score: defaultTo(response.score, 0), // Includes NaN handling
  };
}

// When API returns incomplete data
const userData = processUserData({
  name: null,
  age: undefined,
  score: NaN,
});

console.log(userData);
// { name: 'No name', age: 0, score: 0 }

Can also be used with arrays or objects.

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

const users = defaultTo(response.users, []);
const metadata = defaultTo(response.metadata, {});

// Only handles null/undefined/NaN, not empty arrays or objects
console.log(defaultTo([], ['default'])); // [] (empty array but valid value)
console.log(defaultTo({}, { default: true })); // {} (empty object but valid value)

Parameters

• value (T | null | undefined): The value to check.
• defaultValue (D): The default value to return when the value is null, undefined, or NaN.

Returns

(T | D): Returns the original value if valid, otherwise returns the default value.