isEqual

Performs a deep comparison to check if two values are equal.

const result = isEqual(a, b);

Reference

isEqual(a, b)

Use isEqual when you want to check if two values are deeply equal, including objects, arrays, Date, RegExp, etc. Returns true if the contents are the same even if the references are different. Useful for unit testing and data comparison.

import { isEqual } from 'es-toolkit/predicate';

// Primitive type comparison
isEqual(1, 1); // true
isEqual('hello', 'hello'); // true
isEqual(true, true); // true

// Special value handling
isEqual(NaN, NaN); // true
isEqual(+0, -0); // true

Supports deep comparison of objects and arrays.

import { isEqual } from 'es-toolkit/predicate';

// Deep object comparison
const obj1 = { a: 1, b: { c: 2, d: [3, 4] } };
const obj2 = { a: 1, b: { c: 2, d: [3, 4] } };
isEqual(obj1, obj2); // true

// Array comparison
const arr1 = [1, 2, [3, 4]];
const arr2 = [1, 2, [3, 4]];
isEqual(arr1, arr2); // true

Can also compare objects like Date, RegExp, Map, Set.

import { isEqual } from 'es-toolkit/predicate';

// Date comparison
const date1 = new Date('2020-01-01');
const date2 = new Date('2020-01-01');
isEqual(date1, date2); // true

// RegExp comparison
const regex1 = /hello/g;
const regex2 = /hello/g;
isEqual(regex1, regex2); // true

// Map and Set comparison
const map1 = new Map([['key', 'value']]);
const map2 = new Map([['key', 'value']]);
isEqual(map1, map2); // true

const set1 = new Set([1, 2, 3]);
const set2 = new Set([1, 2, 3]);
isEqual(set1, set2); // true

Frequently used in unit testing.

import { isEqual } from 'es-toolkit/predicate';

function testApiResponse() {
  const expected = { status: 200, data: { message: 'success' } };
  const actual = { status: 200, data: { message: 'success' } };

  if (isEqual(expected, actual)) {
    console.log('Test passed!');
  } else {
    console.log('Test failed!');
  }
}

Parameters

• a (unknown): The first value to compare.
• b (unknown): The second value to compare.

Returns

(boolean): Returns true if the two values are deeply equal, false otherwise.