dequal

What is dequal?

The dequal npm package is a library for performing deep equality checks. It is a lightweight and fast utility for comparing objects, arrays, and other nested data structures to determine if they are equivalent in value.

What are dequal's main functionalities?

Deep equality check for objects

This feature allows you to compare two objects deeply to check if they are equal in value, regardless of whether they are different instances.

const { dequal } = require('dequal');
let obj1 = { a: 1, b: { c: 2 } };
let obj2 = { a: 1, b: { c: 2 } };
console.log(dequal(obj1, obj2)); // true

Deep equality check for arrays

This feature allows you to compare two arrays deeply to check if they are equal in value, including nested arrays.

const { dequal } = require('dequal');
let arr1 = [1, [2, 3]];
let arr2 = [1, [2, 3]];
console.log(dequal(arr1, arr2)); // true

Deep equality check for mixed structures

This feature allows you to compare mixed data structures like objects containing arrays or arrays containing objects to check for deep equality.

const { dequal } = require('dequal');
let mix1 = { a: [1, { b: 2 }] };
let mix2 = { a: [1, { b: 2 }] };
console.log(dequal(mix1, mix2)); // true

Other packages similar to dequal

lodash.isequal

Lodash's isEqual method is a popular utility for performing deep equality checks. It is part of the larger Lodash library, which provides a wide range of utilities for working with JavaScript data types. Compared to dequal, lodash.isequal is part of a larger bundle and may not be as lightweight if you only need the deep equality functionality.

deep-equal

The deep-equal package is another library that provides deep comparison functionality. It is similar to dequal in that it focuses on deep equality checks, but it may have different performance characteristics and API design.

fast-deep-equal

fast-deep-equal is a package that claims to be the fastest deep equality checker. It is similar to dequal in its purpose but may have different implementation details that could affect performance and compatibility in various use cases.

README

dequal

A tiny (304B to 489B) utility to check for deep equality

This module supports comparison of all types, including Function, RegExp, Date, Set, Map, TypedArrays, DataView, null, undefined, and NaN values. Complex values (eg, Objects, Arrays, Sets, Maps, etc) are traversed recursively.

Important:

• key order within Objects does not matter
• value order within Arrays does matter
• values within Sets and Maps use value equality
• keys within Maps use value equality

Install

$ npm install --save dequal

Modes

There are two "versions" of dequal available:

dequal

Size (gzip): 489 bytes
Availability: CommonJS, ES Module, UMD

dequal/lite

Size (gzip): 304 bytes
Availability: CommonJS, ES Module

	IE9+	Number	String	Date	RegExp	Object	Array	Class	Set	Map	ArrayBuffer	TypedArray	DataView
dequal	:x:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:
dequal/lite	:+1:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:white_check_mark:	:x:	:x:	:x:	:x:	:x:

^{Note: Table scrolls horizontally!}

Usage

import { dequal } from 'dequal';

dequal(1, 1); //=> true
dequal({}, {}); //=> true
dequal('foo', 'foo'); //=> true
dequal([1, 2, 3], [1, 2, 3]); //=> true
dequal(dequal, dequal); //=> true
dequal(/foo/, /foo/); //=> true
dequal(null, null); //=> true
dequal(NaN, NaN); //=> true
dequal([], []); //=> true
dequal(
  [{ a:1 }, [{ b:{ c:[1] } }]],
  [{ a:1 }, [{ b:{ c:[1] } }]]
); //=> true

dequal(1, '1'); //=> false
dequal(null, undefined); //=> false
dequal({ a:1, b:[2,3] }, { a:1, b:[2,5] }); //=> false
dequal(/foo/i, /bar/g); //=> false

API

dequal(foo, bar)

Returns: Boolean

Both foo and bar can be of any type.
A Boolean is returned indicating if the two were deeply equal.

Benchmarks

Running Node v10.13.0

The benchmarks can be found in the /bench directory. They are separated into two categories:

• basic – compares an object comprised of String, Number, Date, Array, and Object values.
• complex – like basic, but adds RegExp, Map, Set, and Uint8Array values.

Note: Only candidates that pass validation step(s) are listed.
For example, fast-deep-equal/es6 handles Set and Map values, but uses referential equality while those listed use value equality.

Load times:
  assert             0.109ms
  util               0.006ms
  fast-deep-equal    0.479ms
  lodash/isequal    22.826ms
  nano-equal         0.417ms
  dequal             0.396ms
  dequal/lite        0.264ms

Benchmark :: basic
  assert.deepStrictEqual  x    325,262 ops/sec ±0.57% (94 runs sampled)
  util.isDeepStrictEqual  x    318,812 ops/sec ±0.87% (94 runs sampled)
  fast-deep-equal         x  1,332,393 ops/sec ±0.36% (93 runs sampled)
  lodash.isEqual          x    269,129 ops/sec ±0.59% (95 runs sampled)
  nano-equal              x  1,122,053 ops/sec ±0.36% (96 runs sampled)
  dequal/lite             x  1,700,972 ops/sec ±0.31% (94 runs sampled)
  dequal                  x  1,698,972 ops/sec ±0.63% (97 runs sampled)

Benchmark :: complex
  assert.deepStrictEqual  x    124,518 ops/sec ±0.64% (96 runs sampled)
  util.isDeepStrictEqual  x    125,113 ops/sec ±0.24% (96 runs sampled)
  lodash.isEqual          x     58,677 ops/sec ±0.49% (96 runs sampled)
  dequal                  x    345,386 ops/sec ±0.27% (96 runs sampled)

License

MIT © Luke Edwards