MaxWord.js

// Given a sentence, return the most occurring word

/**
 * @param {string} sentence - the sentence you want to find the most occurring word
 * @returns {string} - the most occurring word
 *
 * @example
 * - maxWord('lala lili lala'); // lala
 */
const maxWord = (sentence = '') => {
 if (typeof sentence !== 'string') {
 throw new TypeError('the param should be string')
 }

 if (!sentence) {
 return null
 }

 const words = sentence.split(' ')
 if (words.length < 2) {
 return words[0]
 }

 const occurrences = {}
 words.forEach((word) => {
 occurrences[word.toLocaleLowerCase()] =
 occurrences[word.toLocaleLowerCase()] + 1 || 1
 })

 const max = Object.keys(occurrences).reduce(
 (n, word) => {
 if (occurrences[word] > n.count) {
 return { word, count: occurrences[word] }
 } else {
 return n
 }
 },
 { word: '', count: 0 }
 )

 return max.word
}

export { maxWord }