@zerodep/is-equal

A performant utility to compare two values for equality by value (not by reference). Incomparable items will throw an error.

Full documentation is available at the zerodep.app page.

Signature

declare const isEqual: (value1: unknown, value2: unknown) => boolean;

Examples

All @zerodep packages support both ESM and CJS formats, each complete with Typescript typings.

// ESM
import { isEqual } from '@zerodep/is-equal';

// CJS
const { isEqual } = require('@zerodep/is-equal');

// Arrays - size and order of items must be identical
isEqual([], []); // true
isEqual([1, 2], [1, 2]); // true
isEqual([1, 2], [2, 1]); // false
isEqual([1, 2], [1, 2, 3]); // false
isEqual(['a', 'b', 'c'], ['c', 'b', 'a']); // false
isEqual(['a', 'b', 'c'], ['a', 'b', 'c', 'd']); // false
isEqual(['b', [2, 4, ['c', 'd', 6]]], ['b', [2, 4, ['c', 'd', 6]]]); // true
isEqual(['b', [2, 4, ['c', 'd', 6]]], [[4, ['c', 'd', 6], 2], 'b']); // false

// BigInts - must have identical values
isEqual(42n, 42n); // true
isEqual(0n, 0); // false
isEqual(8675309n, BigInt(8675309)); // true

// Booleans
isEqual(true, true); // true
isEqual(true, false); // false
isEqual(true, new Boolean(true)); // true

// Dates - are compared by value
isEqual(new Date('2000-01-01T00:00:00.000Z'), new Date('2000-01-01T00:00:00.000Z')); // true
isEqual(new Date('2000-01-01T00:00:00.000Z'), new Date('1999-12-31T23:59:59.999Z')); // false

// Empty
isEqual(null, null); // true
isEqual(undefined, undefined); // true
isEqual(null, undefined); // false

// Errors - are compared by type and attributes
isEqual(new Error('message'), new Error('message')); // true
isEqual(new Error('message'), new Error('xxxx')); // false
isEqual(new TypeError('error'), new RangeError('error')); // false

// Floats
isEqual(0.08, 0.08); // true
isEqual(Math.PI, Math.PI); // true
isEqual(-273.15, new Number(-273.15)); // false

// Functions
isEqual(
  () => 'function',
  () => 'function'
); // true
isEqual(
  () => 'xxxx',
  () => 'yyyy'
); // false

// Generators - cannot be compared
isEqual(
  function* () {
    yield 'a';
  },
  function* () {
    yield 'a';
  }
); // false
isEqual(
  function* () {
    yield 'a';
  },
  function* () {
    yield 'b';
  }
); // false

// Maps
isEqual(new Map(), new Map()); // true
isEqual(new Map([['key1', 123]])), new Map([['key1', 123]]); // true
isEqual(new Map([['key1', 123]])), new Map([['2key', 123]]); // false
isEqual(new Map([['key1', 123]])), new Map([['key1', 456]]); // false
isEqual(new Map([['key1', 123]], ['key2', 456])),
  new Map([
    ['key1', 123],
    ['key2', 456],
  ]); // true
isEqual(new Map([['key1', 123]], ['key2', 456])),
  new Map([
    ['key2', 456],
    ['key1', 123],
  ]); // true
isEqual(new Map([['key1', 123]], ['key2', 456])), new Map([['key1', 123]]); // false

// Numbers
isEqual(0, 0); // true
isEqual(0, -0); // false  <-- these are indeed different
isEqual(3e8, 3e8); // true
isEqual(1234, 5678); // false
isEqual(Infinity, Infinity); // true
isEqual(Infinity, -Infinity); // false
isEqual(Number.MAX_SAFE_INTEGER, Number.MAX_SAFE_INTEGER); // true
isEqual(Number.MAX_SAFE_INTEGER, Number.MIN_SAFE_INTEGER); // false
isEqual(Number.NaN, Number.NaN); // true
isEqual(2161, new Number(2161)); // false

// POJOs - are deeply compared by value
isEqual({}, {}); // true
isEqual({ key: 'string' }, { key: 'string' }); // true
isEqual({ key: [1, 2, 3] }, { key: [1, 2, 3] }); // true
isEqual({ key: [1, 2, 3] }, { key: [3, 2, 1] }); // false
isEqual({ a: 1, b: { c: [1, 2] } }, { a: 1, b: { c: [1, 2] } }); // true
isEqual({ a: 1, b: { c: [1, 2] } }, { b: { c: [1, 2] }, a: 1 }); // true
isEqual({ a: 1, b: { c: [1, 2] } }, { b: 1, c: { d: [1, 2] } }); // false
isEqual({ a: 1, b: { c: [1, 2] } }, { a: 1, b: { c: [2, 1] } }); // false

// Promises - cannot be compared
isEqual(new Promise(() => {}), new Promise(() => {})); // false
isEqual(Promise.all([]), Promise.all([])); // false
isEqual(Promise.allSettled([]), Promise.allSettled([])); // false
isEqual(Promise.race([]), Promise.race([])); // false
isEqual(Promise.resolve(), Promise.resolve()); // false

// Regular Expression
isEqual(/[aeiou]+/gi, /[aeiou]+/gi); // true
isEqual(new RegExp('d', 'gi'), new RegExp('d', 'gi')); // true
isEqual(/[aeiou]+/gi, new RegExp('[aeiou]+', 'gi')); // true
isEqual(new RegExp('abc'), new RegExp('def')); // false

// Sets
isEqual(new Set(), new Set()); // true
isEqual(new Set([1, 2, 3])), new Set([1, 2, 3]); // true
isEqual(new Set([1, 2, 3])), new Set([3, 2, 1]); // true  <-- CAUTION: sets are unordered
isEqual(new Set([1, 2, 3])), new Set([1, 2]); // false

// Strings
isEqual('', ''); // true
isEqual('asdf', 'asdf'); // true
isEqual('asdf', 'qwerty'); // false
isEqual('G', new String('G')); // true

// Symbols - cannot be compared
isEqual(Symbol(), Symbol()); // throws ZeroDepError - Cannot compare Symbol values
isEqual(Symbol('val1'), Symbol('val1')); // throws ZeroDepError - Cannot compare Symbol values

// TypedArrays
isEqual(new Int8Array(2), new Int8Array(2)); // true
isEqual(new SharedArrayBuffer(2), new SharedArrayBuffer(2)); // throws ZeroDepError - Cannot compare SharedArrayBuffer values

// WeakMap and WeakSet - cannot be compared
isEqual(new WeakMap(), new WeakMap()); // throws ZeroDepError - Cannot compare WeakMap values
isEqual(new WeakSet(), new WeakSet()); // throws ZeroDepError - Cannot compare WeakSet values

---

## ZeroDep Advantages

- **Zero npm dependencies** - completely eliminates all risk of supply-chain attacks, decreases node_modules folder size
- **ESM & CJS** - has both ecmascript modules and common javascript exports
- **Tree Shakable** - built to be fully tree shakable ensuring your packages are the smallest possible size
- **Fully typed** - typescript definitions are provided for every package for a better developer experience
- **Semantically named** - package and method names are easy to grok, remember, use, and read
- **Documented** - actually useful documentation with examples at [zerodep.app](https://zerodep.app)
- **Intelligently Packaged** - multiple npm packages of different sizes available allowing a menu or a-la-carte composition of capabilities
- **100% Tested** - all methods and packages are fully unit tested
- **Predictably Versioned** - semantically versioned for peace-of-mind upgrading, this includes changelogs
- **MIT Licensed** - permissively licensed for maximum usability