group by code, turn array order buy property

groupby.ts

declare global {
  interface Array<T> {
    groupBy(elem: T): Array<T>;
  }
}

Array.prototype.groupBy = function(prop) {
  return this.reduce(function(groups, item) {
    const val = item[prop]
    groups[val] = groups[val] || []
    groups[val].push(item)
    return groups
  }, {})
}

// ussing
news = news.groupBy('localeDate');