defaults

What is defaults?

The `defaults` npm package is primarily used for merging a set of default properties with user-provided options. It is particularly useful in situations where you want to ensure that an object contains a certain set of properties with default values, even if some of those properties are not provided by the user. This can be very handy in configuration objects for libraries, APIs, or any other modular pieces of code that require a predictable structure of input options.

What are defaults's main functionalities?

Merging default options with user options

This feature allows the merging of a user-provided options object with a default options object. If the user provides a value for a given property, that value is used; otherwise, the default value is applied. This is particularly useful for configuring applications or modules where certain parameters are optional but should have a defined default behavior.

{"const defaults = require('defaults');\nconst userOptions = { color: 'blue' };\nconst defaultOptions = { color: 'red', size: 'large' };\nconst options = defaults(userOptions, defaultOptions);\nconsole.log(options); // Output: { color: 'blue', size: 'large' }"}

Other packages similar to defaults

lodash.merge

Lodash's `merge` function offers deep merging capabilities, which can be more comprehensive than the shallow merge provided by `defaults`. It allows for the merging of nested properties, which is useful when dealing with complex object structures. However, for simple use cases, `defaults` might be more straightforward and lightweight.

deep-extend

Similar to `lodash.merge`, `deep-extend` provides deep merging functionality. It is designed to recursively merge properties of objects, making it suitable for complex configurations. Compared to `defaults`, `deep-extend` offers a more robust solution for nested properties but might be overkill for simple scenarios.

README

defaults

A simple one level options merge utility

Install

npm install defaults

Usage

const defaults = require('defaults');

const handle = (options, fn) => {
	options = defaults(options, {
		timeout: 100
	});

	setTimeout(() => {
		fn(options);
	}, options.timeout);
}

handle({timeout: 1000}, () => {
	// We're here 1000 ms later
});

handle({timeout: 10000}, () => {
	// We're here 10s later
});

Summary

this module exports a function that takes 2 arguments: options and defaults. When called, it overrides all of undefined properties in options with the clones of properties defined in defaults

Sidecases: if called with a falsy options value, options will be initialized to a new object before being merged onto.