JAVASCRIPT

cypress have attribute

cy.get('selector')
	.should('have.attr', 'aria-checked', 'true')

cypress check attribute for each element

cy.get('ul')
  .find('li')
  .each((el) => {
  	expect(Cypress.$(el)).to.have.class(
  		'classname'
  	)
 })

cypress check element have attribute

cy.get('input').invoke('attr', 'placeholder').should('contain', 'username')

cypress check element have attribute

// have.attr comes from chai-jquery
cy.get('#header a').should('have.attr', 'href', '/users')

cypress check element has an attribute

let $el = Cypress.$("myselector");
if ($el.attr("myattr") === "myvalue") {
    do.A();
} else {
    do.B();
}