Chart.js/test/specs/core.helpers.tests.js

describe('Core helper tests', function() {

	var helpers;

	beforeAll(function() {
		helpers = window.Chart.helpers;
	});

	it('should generate integer ids', function() {
		var uid = helpers.uid();
		expect(uid).toEqual(jasmine.any(Number));
		expect(helpers.uid()).toBe(uid + 1);
		expect(helpers.uid()).toBe(uid + 2);
		expect(helpers.uid()).toBe(uid + 3);
	});

	describe('clone', function() {
		it('should not allow prototype pollution', function() {
			const test = helpers.clone(JSON.parse('{"__proto__":{"polluted": true}}'));
			expect(test.prototype).toBeUndefined();
			expect(Object.prototype.polluted).toBeUndefined();
		});
	});
});