toContainEqual()

The toContainEqual() method asserts that an array or set contains an element that is deeply equal to the expected value, using the same equality logic as toEqual().

Syntax

expect(actual).toContainEqual(expected);
expect(actual).not.toContainEqual(expected);

Parameters

Parameter	Type	Description
expected	any	The value to search for using deep equality

Returns

Type	Description
void	No return value

Description

The toContainEqual() method checks if an array or set contains an element that is deeply equal to the expected value. Unlike toContain(), which uses strict equality (===), toContainEqual() performs deep equality comparison, making it suitable for finding objects with matching content even if they are different instances.

Usage

import http from 'k6/http';
import { expect } from 'https://jslib.k6.io/k6-testing/0.6.1/index.js';

export default function () {
  const response = http.get('https://quickpizza.grafana.com/');

  // Create test data to demonstrate toContainEqual
  const pizzaOptions = [
    { name: 'Margherita', toppings: ['tomato', 'mozzarella'] },
    { name: 'Pepperoni', toppings: ['tomato', 'mozzarella', 'pepperoni'] },
    { name: 'Veggie', toppings: ['tomato', 'mozzarella', 'peppers'] },
  ];

  // Check if array contains specific pizza objects
  expect(pizzaOptions).toContainEqual({
    name: 'Margherita',
    toppings: ['tomato', 'mozzarella'],
  });

  // Works with various data types
  const mixedArray = ['string', 123, { key: 'value' }, [1, 2, 3]];
  expect(mixedArray).toContainEqual({ key: 'value' });
  expect(mixedArray).toContainEqual([1, 2, 3]);
  expect(mixedArray).not.toContainEqual({ key: 'different' });
}