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TypeScript-first deep equivalence comparison between two values

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Equivalent comparison of Object data structures. It supports many built-in objects and can be compared with Date, Array or Object.

The supported built-in objects are here.

It provides equal functions and specific data types functions . The equal function works correctly in all situations. The specific data types functions works correctly only for specific data types, but it has good performance. Please check bundle size optimization for details.

🔖 Table of Contents

✨ Features

  • ⚡ Multi runtime support (Deno, Node.js and Browsers)
  • 📚 Pure TypeScript and provides type definition
  • Rambda's all test case is passed
  • 🌎 Universal module, providing ES modules and Commonjs
  • 📦 Optimized, super slim size
  • 📄 TSDoc-style comments

Package name

Deno: equal (,

Node.js: lauqe (npm)

⚡ Example

equal("", ""); // true
equal(NaN, NaN); // true
equal(0, 0); // true
equal(+0, 0); // true
equal(-0, 0); // true
equal(+0, -0); // true
equal(0n, 0n); // true
equal(undefined, undefined); // true
equal(null, null); // true
equal(undefined, null); // false
equal(true, false); // false
const symbol = Symbol("hello");
equal(symbol, symbol); // true
equal(Symbol("hello"), Symbol("hello")); // false
equal({}, {}) // true
equal({ "": undefined }, { "": undefined }) // true
equal({ "": undefined }, { "": undefined, a: 1 }) // false
equal({ a: 1, b: undefined}, { b: undefined, a: 1}) // true
equal([], []) // true
equal([[[]]], [[[]]]) // true
equal(new Date("2000/1/1"), new Date("2000/1/1")) // true
equal(() => true, () => true) // true
equal(AggregateError([ Error("error"), TypeError("type error") ]), AggregateError([ Error("error"), TypeError("type error") ])) // true
equal(/s/, /s/) // true
equal(new String('hello'), new String('hello')) // true
equal(new Number(0), new Number(0)) // true
equal(new Boolean(true), new Boolean(true)) // true
equal(new Map([[1, 2], [3, 4]]), new Map([[3, 4], [1, 2]]) // true

💫 Usage

equal provides multi platform modules.

🦕 Deno

import { equal } from "";

equal([1, 2, 3], [1, 2, 3]); // true
import { equal } from "";

equal([1, ['hello', ['world']], [1, ['hello', ['world']]); // true

📦 Node.js

NPM package name is lauqe .


npm i lauqe
yarn add lauqe

ES modules

import { equal } from "lauqe";

equal(new Date("2000/1/1"), new Date("2000/1/1")); // true


const { equal } = require("lauqe");

equal(/hello/g, /hello/g); // true

🌐 Browser

The module that bundles the dependencies is obtained from skypack.

<script type="module">
  import { equal } from "";
  console.log(equal(() => {}, () => {}); // true


Definition of Equality

Equality is defined as the data structure and property values are equivalent.


Numerical equivalence is based on Same-value-zero.
That is, all of the following comparisons are considered equivalent.

equal(NaN, NaN); // true
equal(0, 0); // true
equal(+0, 0); // true
equal(-0, 0); // true
equal(+0, -0); // true

Built-in objects

The following objects work correctly.

Do not guarantee the behavior of objects not on this list.

Bundle size optimization

The equal function works correctly for all supported built-in objects. The price is an increase in bundle size.

If the data to be compared for equivalence is of multiple data types, or if the data types are unclear, the equal function may be the best choice.

If the data type is predetermined, you can reduce the bundle size by using the specific function instead.

Type definition


Compare the equivalence of the all supported built-in objects and primitive values .

declare const equal: <T, U extends T>(a: T, b: U) => boolean;
Parameter Description
a Any value
b Any value

=> Return true if the reference memory is the same or the property members and their values are the same


Compare the equivalence of Date objects.

declare const equalDate: (a: Date, b: Date) => boolean;
equalDate(new Date(0), new Date(0)) // true
equalDate(new Date(0), new Date(1)) // false
equalDate(new Date("1999/1/1 00:00:01"), new Date("1999/1/1")) // false
// invalid date
[new Date("a"), new Date("a"), true],
[new Date("a"), new Date("b"), true],


Compare the equivalence of Primitive values.

declare const equalPrimitive: <T extends Primitive, U extends T>(
  a: T,
  b: U,
) => boolean;

type Primitive =
  | string
  | number
  | bigint
  | boolean
  | symbol
  | undefined
  | null;
equalPrimitive(NaN, NaN); // true
equalPrimitive(0, +0); // true
equalPrimitive(-0, +0); // true


Compare the equivalence of the Error object and its Derived object.

declare const equalError: (a: Error, b: Error) => boolean;
equalError(Error("test"), Error("test")); // true
); // true
equalError(Error("test"), Error("hello")); // false
equalError(Error("test"), TypeError("test")); // false


Compare the equivalence of URL objects.

declare const equalURL: (a: URL, b: URL) => boolean;
equalURL(new URL("", "")); // true
equalURL(new URL("", "")); // true


Compare the equivalence of ArrayBuffer objects.

declare const equalArrayBuffer: (a: ArrayBuffer, b: ArrayBuffer) => boolean;


equalArrayBuffer(new ArrayBuffer(0), new ArrayBuffer(0)); // true
equalArrayBuffer(new ArrayBuffer(0), new ArrayBuffer(1)); // false

💚 Supports

ie is no longer supported to reduce bundle size.

The TypeScript version must be 4.1.0 or higher.

This project provides ES modules and Commonjs.

If you have an opinion about what to support, you can open an issue to discuss it.

The browserslist has the following settings.

last 8 version
not IE <= 11
not ie_mob <= 11
node 6
IE / Edge
iOS Safari
iOS Safari
^1.6.0 ^6.17.0 ^83 ^78 ^83 ^11 ^12.0 ^7.2 ^68

🤝 Contributing

Contributions, issues and feature requests are welcome!
Feel free to check issues.

Contributing guide

🌱 Show your support

Give a ⭐️ if this project helped you!

💡 License

Copyright © 2021-present TomokiMiyauci.

Released under the MIT license