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Fast deep equal

Version published
Install size
13.5 kB

Package description

What is fast-deep-equal?

The fast-deep-equal package is a fast deep equality comparison library. It allows developers to check if two objects, arrays, or values are deeply equal to each other, meaning that their structure and nested values are identical.

What are fast-deep-equal's main functionalities?

Deep equality check for objects

This feature allows you to compare two objects to determine if they are deeply equal.

const equal = require('fast-deep-equal');
const obj1 = { a: 1, b: { c: 2 } };
const obj2 = { a: 1, b: { c: 2 } };
console.log(equal(obj1, obj2)); // true

Deep equality check for arrays

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

const equal = require('fast-deep-equal');
const arr1 = [1, 2, [3, 4]];
const arr2 = [1, 2, [3, 4]];
console.log(equal(arr1, arr2)); // true

Deep equality check for values

This feature allows you to compare two primitive values to determine if they are equal.

const equal = require('fast-deep-equal');
const val1 = 'value';
const val2 = 'value';
console.log(equal(val1, val2)); // true

Other packages similar to fast-deep-equal




The fastest deep equal with ES6 Map, Set and Typed arrays support.

Build Status npm Coverage Status


npm install fast-deep-equal


  • ES5 compatible
  • works in node.js (8+) and browsers (IE9+)
  • checks equality of Date and RegExp objects by value.

ES6 equal (require('fast-deep-equal/es6')) also supports:

  • Maps
  • Sets
  • Typed arrays


var equal = require('fast-deep-equal');
console.log(equal({foo: 'bar'}, {foo: 'bar'})); // true

To support ES6 Maps, Sets and Typed arrays equality use:

var equal = require('fast-deep-equal/es6');
console.log(equal(Int16Array([1, 2]), Int16Array([1, 2]))); // true

To use with React (avoiding the traversal of React elements' _owner property that contains circular references and is not needed when comparing the elements - borrowed from react-fast-compare):

var equal = require('fast-deep-equal/react');
var equal = require('fast-deep-equal/es6/react');

Performance benchmark

Node.js v12.6.0:

fast-deep-equal x 261,950 ops/sec ±0.52% (89 runs sampled)
fast-deep-equal/es6 x 212,991 ops/sec ±0.34% (92 runs sampled)
fast-equals x 230,957 ops/sec ±0.83% (85 runs sampled)
nano-equal x 187,995 ops/sec ±0.53% (88 runs sampled)
shallow-equal-fuzzy x 138,302 ops/sec ±0.49% (90 runs sampled)
underscore.isEqual x 74,423 ops/sec ±0.38% (89 runs sampled)
lodash.isEqual x 36,637 ops/sec ±0.72% (90 runs sampled)
deep-equal x 2,310 ops/sec ±0.37% (90 runs sampled)
deep-eql x 35,312 ops/sec ±0.67% (91 runs sampled)
ramda.equals x 12,054 ops/sec ±0.40% (91 runs sampled)
util.isDeepStrictEqual x 46,440 ops/sec ±0.43% (90 runs sampled)
assert.deepStrictEqual x 456 ops/sec ±0.71% (88 runs sampled)

The fastest is fast-deep-equal

To run benchmark (requires node.js 6+):

npm run benchmark

Please note: this benchmark runs against the available test cases. To choose the most performant library for your application, it is recommended to benchmark against your data and to NOT expect this benchmark to reflect the performance difference in your application.

Enterprise support

fast-deep-equal package is a part of Tidelift enterprise subscription - it provides a centralised commercial support to open-source software users, in addition to the support provided by software maintainers.

Security contact

To report a security vulnerability, please use the Tidelift security contact. Tidelift will coordinate the fix and disclosure. Please do NOT report security vulnerability via GitHub issues.





Last updated on 08 Jun 2020

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