Function skipNonPracticeLevels

app/core/utils.js:976–981

(levels, index)

const isPractice = level => level != null ? level.practice : undefined

const skipNonPracticeLevels = function (levels, index) {
  while ((index >= 0) && !isPractice(levels[index])) {
    index--
  }
  return index
}

const skipPracticeLevels = function (levels, index) {
  while ((index >= 0) && isPractice(levels[index])) {