JavaScript word count, 5 mins kata

word-count-kata.js

// task: count frequency of words in a string

// assumptions:
// - "words" are separated by spaces
// - input will always be a string, never undefined/null etc.
// - numbers and emoji are "words"
// - input will be latin script

// steps:
// - split input by ' '
// - loop through and add found instances to a map of word: count
//     - if not found, add key else just add to value

// time complexity: O(n)

const text = '😍 this is an input, a really really nice input of more than 10 characters, and it has various words within it 😍';

const countWords = (input) => {
  if (!input instanceof String) {
    return [];
  }
  
  const counts = input.split(' ').reduce((count, word) => {
    count.set(word, (count.get(word) || 0) + 1);
    return count;
  }, new Map());

  return [...counts.entries()].sort((left, right) => right[1] - left[1]);
};

console.log(countWords(text));