adam bien's blog

Accessing Shadow DOM inside a Web Component from Cypress 📎

A Custom Element with a input field placed inside a Shadow DOM:


class ShadowInput extends HTMLElement { 

    constructor() { 
        super();
        this.root = this.attachShadow({mode:"open"});
    }

    connectedCallback() { 
        this.root.innerHTML = `
            <input placeholder="something"></input>
        `;
    }
}
customElements.define('shadow-input',ShadowInput);

can be tested with cypress.io by accessing the native input field by querying the shadowRoot:


context('the shadow', () => {
    beforeEach(() => {
        cy.visit('localhost:3000');
    })
    
    it('custom text field', () => {
        cy.get('shadow-input').should(e => { 
        const [dom] = e.get();
        dom.shadowRoot.querySelector('input').value = "hey duke";
        });
    });  
    })

See it in action and "from scratch":

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