fast-is-equal

fast-is-equal

⚡️Blazing-fast equality checks, minus the baggage. A lean, standalone alternative to Lodash's isEqual - because speed matters.

Why fast-is-equal?

• 🚀 Lightning Speed: Up to 55.84x faster than Lodash's isEqual (average 11.73x faster across 49 test cases).
• 🪶 Lightweight: Dependency-free, minimal footprint.
• 🔄 Versatile: Handles primitives, objects, arrays, Maps, Sets, typed arrays, circular references, and more.
• 🏆 Proven: Outperforms Lodash in 93.9% of benchmark cases.

Installation

Using yarn:

yarn add fast-is-equal

Using npm:

npm install fast-is-equal

Usage

import { fastIsEqual } from 'fast-is-equal';

console.log(fastIsEqual(1, 1)); // true
console.log(fastIsEqual({ a: 1 }, { a: 1 })); // true
console.log(fastIsEqual([1, 2], [1, 3])); // false

Performance Benchmarks

fast-is-equal was tested against Lodash's isEqual across 49 diverse test cases with 1,000,000 iterations each. The results speak for themselves:

Key Highlights

• Average Speed: fastIsEqual is 11.73x faster (0.000172 ms vs. 0.002013 ms).
• Win Rate: Outperforms Lodash in 46/49 cases (93.9%).
• Peak Performance: Up to 55.84x faster for large Sets.

Top 10 Performance Gains

Test Case	fastIsEqual (ms)	Lodash isEqual (ms)	Speed Boost
Large Set (100 items)	0.000673	0.037564	55.84x 🚀
Map vs Set	0.000018	0.000485	26.52x 🚀
Large Map (50 entries)	0.001059	0.025756	24.32x 🚀
Map with primitives	0.000092	0.001487	16.09x 🚀
Map (unequal)	0.000092	0.001406	15.29x 🚀
Large TypedArray (1000)	0.000944	0.013165	13.95x 🚀
ArrayBuffer (small)	0.000092	0.001263	13.74x 🚀
Empty Set	0.000058	0.000691	11.96x 🚀
Empty Map	0.000058	0.000684	11.84x 🚀
Set of strings	0.000082	0.000940	11.51x 🚀

Performance Across Categories

• Primitives: Competitive performance with smart optimizations for edge cases like NaN
• Objects: 1.59x–2.87x faster, with best gains on simple and nested structures
• Arrays: 1.24x–4.38x faster, excelling at primitive arrays and sparse arrays
• TypedArrays: 11.30x–13.95x faster, dramatically outperforming on all variants
• Special Objects: 8.63x–10.25x faster for Dates and RegExp
• Collections: 10.84x–55.84x faster for Maps and Sets, with exceptional gains on large collections
• Circular References: 3.04x–3.72x faster with optimized cycle detection

Detailed Benchmark Results

Run yarn benchmark or npm run benchmark to test locally. Full results available in benchmarks/results.txt.

Edge Cases Where Lodash Wins

Only 3 cases where Lodash marginally outperforms (by less than 5%):

• String vs Number: 0.95x slower
• Large Numbers: 0.99x slower
• Boolean vs Number: 0.99x slower

These represent cross-type comparisons with negligible real-world impact.

Features

• Dependency-Free: No bloat, just performance.
• Comprehensive: Supports all JavaScript types, including edge cases like circular references and typed arrays.
• Optimized: Fine-tuned for real-world use cases (e.g., API responses, state objects).

License

MIT

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Changelog

1.2.3 (2025-05-31)

Bug Fixes

• improve type checking and add support for Symbol, BigInt, and DataView (4f66af2)