defaults-deep-safe

A deep version of _.defaults(object, [sources]), safe by default by deep cloning each source. Arrays are not merged.

Status

Installation

Install the package via npm:

❯ npm install defaults-deep-safe

Usage

Arguments

1. object (Object): The destination object.
2. [source] (...Object): The source objects.

Returns

(Object): Returns the destination object.

Example

const defaultsDeep = require('defaults-deep-safe');

const object = { foo: 'bar', bar: { biz: { net: 'qux' } }, qux: ['biz'] };
const source = { bar: { biz: { net: 'txi', qox: 'fuc' } }, qux: ['baz'] };

defaultsDeep(object, source);
// => { foo: 'bar', bar: { biz: { net: 'qux', qox: 'fuc' } }, qux: ['biz'] }

Or as a lodash mixin:

const _ = require('lodash');

_.mixin({
  defaultsDeep: require('defaults-deep-safe')
});

_.defaultsDeep(object, [sources]);

Motivation

This module is perfect for merging config/settings files and to safely handle options by avoiding changing objects by reference.

Here's a quick example demonstrating why using _.defaults may not be a safe operation:

const foo = { a: 1, c: 2 };
const bar = { b: new Date(), d: { e: 'f' } };

const result = require('lodash').defaults(foo, bar);

require('assert')(bar.b === result.b);
// => true

require('assert')(bar.d === result.d);
// => true

result.d.g = 'h';

console.log(bar.d);
// => { e: 'f', g: 'h' }

Using defaults-deep-safe:

const foo = { a: 1, c: 2 };
const bar = { b: new Date(), d: { e: 'f' } };

const result = require('defaults-deep-safe')(foo, bar);

require('assert')(bar.b === result.b);
// => AssertionError: false == true

require('assert')(bar.d === result.d);
// => AssertionError: false == true

result.d.g = 'h';

console.log(bar.d);
// => { e: 'f' }

Tests

❯ npm test

License

MIT