Top K Frequent Words

topKFrequent.ts

const groupByFrequency = (acc, x) => ({ ...acc, [x]: (acc[x] || 0) + 1 })
const sortFrequency = (a, b) => (
  b[1] === a[1]
    ? (b[0] < a[0] ? 1 : -1) // Sort same frequent words alphabetical
    : (b[1] > a[1] ? 1 : -1) // Sort frequency from highest to lowest
)

function topKFrequent(words: string[], k: number): string[] {
  return Object.entries(words.reduce(groupByFrequency, {}))
   .sort(sortFrequency)
   .map(x => x[0])
   .slice(0, k)
};