newfilereader.js

const imageBinary = null
const changeImagenUpdate = (e) => {
        e.preventDefault();
        const imageSelected = e.target.files[0];
        
        const reader = new FileReader();
        reader.readAsDataURL(imageSelected);
        reader.onload = e => {
            e.preventDefault();
            imageBinary = e.target.result
        }
    }
        
    const imageEl =  document.getElementById('imagenId')
    imageEl.src = imageBinary