Word count and sort module

wordCount.js

export const IGNORE_WORDS = ['', 'a', 'an', 'and', 'as', 'be', 'by', 'for', 'has', 'he', 'her', 'hers', 'him', 'his', 'in', 'it', 'of', 'or', 'our', 'ours', 'the', 'their', 'theirs', 'this', 'to', 'us', 'was', 'we', 'were'];

/**
 * Sort counted words by their count in descending order
 * 
 * @param {Object} wordCounts Dictionary of words and counts
 * @returns {Object} Sorted dictionary of word counts
 */
export function sortByCount(wordCounts) {
	let sorted = {};

	Object.keys(wordCounts)
		.sort((a, b) => {
			// Sort by count in descending order
			if (wordCounts[a] < wordCounts[b]) {
				return 1;
			} else if (wordCounts[a] > wordCounts[b]) {
				return -1;
			}
			// Sort alphabetically in ascending order for like counts
			else if (a.toLowerCase() > b.toLowerCase()) {
				return 1;
			} else if (a.toLowerCase() < b.toLowerCase()) {
				return -1;
			}

			return 0;
		})
		.forEach(word => sorted[word] = wordCounts[word]);

	return sorted;
}

/**
 * Split text into words
 *
 * Removes IGNORE_WORDS and can optionally ignore case sensitivity.
 *
 * @param {String} text Corpus of text to split
 * @param {Object} options
 *     @param {Boolean} caseSensitive (false) Respect case sensitivity
 *     @param {Boolean} removeIgnoredWords (true) Include all words in the returned Array
 * @returns {Array} Array of words
 */
export function words(text, options = { caseSensitive: false, removeIgnoredWords: true }) {
	const { caseSensitive, removeIgnoredWords } = options;

	let words = (caseSensitive ? text : text.toLowerCase()).split(' ')
		// Trim punctuation
		.map(word => word.replace(/^[^\w]+|[^\w]+$/, ''))

	if (removeIgnoredWords) {
		words = words.reduce((words, word) => !IGNORE_WORDS.includes(word) ? [...words, word] : words, []);
	}

	return words;
}

/**
 * Count unique instances of words
 * 
 * @param {Array} words Array of words to count uniquely
 * @returns {Object} Dictionary of word counts
 */
export function wordCounts(words) {
	return words.reduce((obj, word) => ({
		...obj,
		[word]: (obj[word] || 0) + 1
	}), {})
}