Find the prominent images on the page

getProminent.coffee

getProminent = (limit = 25, minPixelCount = 50000) ->
  imageEls = document.getElementsByTagName 'img'
  matches = []
 
  sortCollection = (collection, key) ->
    collection.sort (a, b) ->
      b[key] - a[key]
 
  isInCollection = (collection, key, value) ->
    collection.some (model) ->
      model[key] is value
 
  storeProminent = (image) ->
    unless isInCollection(matches, 'src', image.src) or image.pixelCount < minPixelCount
      matches.push image
 
  images = for image in imageEls
      src: image.src
      width: image.naturalWidth
      height: image.naturalHeight
      pixelCount: image.naturalWidth * image.naturalHeight
 
  storeProminent image for image in images
  
  sortCollection(matches, 'pixelCount').slice(0,limit)

getProminent.js

function getProminent(limit = 25, minPixelCount = 50000) {
    const imageEls = document.getElementsByTagName("img");
    const images = [];

    const sortCollection = (collection, key) => {
        return collection.sort((a, b) => b[key] - a[key]);
    };

    const isInCollection = (collection, key, value) => {
        return collection.some((model) => model[key] === value);
    };

    for (let i = 0; i < imageEls.length; i++) {
        const imageEl = imageEls[i];

        const duplicate = isInCollection(images, "src", imageEl.src);

        const image = {
            src: imageEl.src,
            width: imageEl.naturalWidth,
            height: imageEl.naturalHeight,
            pixelCount: imageEl.naturalWidth * imageEl.naturalHeight
        };

        if (!duplicate && image.pixelCount > minPixelCount) {
            images.push(image);
        }
    }

    return sortCollection(images, "pixelCount").slice(0, limit);
};