breadthFirstSearch.js

function find(array, searchCriteria) {

  let current = array
  let next = []
 

  while (current) {

    if (searchCriteria(current)) {
      return current
    }

    if (Array.isArray(current)) {
      for (let i = 0; i < current.length; i++) {
        next.push(current[i])
      }
    }

    current = next.shift()
  }

  return null
}