Reusable ES6 code to transform <img> DOM elements into <figures> with the image's alt text as a <figcaption>

imgsToFigs.js

let processImages = (selector) => {
    let container = document.querySelector(selector)
    let images = Array.from(container.getElementsByTagName('img'))
    images.forEach((e, a, i) => {
      if (!(e.getAttribute('data-processed'))) {
        let fig = document.createElement('figure')
        fig.innerHTML = `<img data-processed="true" src="${e.src}"><figcaption>${e.alt}</figcaption>`
        e.parentNode.replaceChild(fig, e)
      }
    })
  }

// usage: 
processImages('.content')