This little scripts looks for children of an element that has a class name

get-child-with-classname.js

 function getChildWithClassName(element, className) {
    if (!element || !className) return null;

    const toIterable = elemList => (elemList ? [...elemList] : [])
    const searcher = nodes => {
      if (!nodes || nodes.length < 1) return null;
      return nodes.find(node => toIterable(node.classList).includes(className))
        || nodes.map(node => searcher(toIterable(node.childNodes))).find(x => x) // 🚀
    }

    return searcher(toIterable(element.childNodes));
  }