How to console text in an element using Cypress?

I am using Cypress for testing. I want to make sure that certain data is collected when on the page, but that does not show in the html. I have added hidden html elements for this purpose, which looks like this:

<div class="hidden">
    <p id="c.campaign">3005</p>
</div>

Now I want to use my Cypress test to make sure that there is a campaign saved to the page. This is what I have so far:

cy.get('#c.campaign').should('not.be.visible').invoke('text').then((text) => {
    cy.log(text)
})

The should not be visible is necessary as the element it hidden and does not find it otherwise. It should be logging 3005 but nothing is appearing.