vocab.js

(({ strict = false, sort = true, trim = true, search = false } = {}) => {
	const suffixes = ['s', 'ly', 'ing', 'd', 'ed', 'er', 'r', 'est', 'ist', 'al', 'ism', 'ity', 'ic'];
	const isSuffixed = (string, strings, suffix) => string.endsWith(suffix) && strings.includes(string.substring(0, string.length - suffix.length));
	const matchSearch = typeof search == 'string' ? e => e.includes(search)
		: search instanceof RegExp ? e => e.match(search)
		: search === false ? e => true
		: search instanceof Array ? e => search.includes(e)
		: typeof search == 'function' ? search
		: (() => { throw new TypeError(`Search argument was ${typeof search}: ${search}`); })();
	const words = strict
		? document.body.innerText.split(/\s+/)
		: document.body.innerText.toLowerCase().split(/[^a-z]/);
	const vocab = [...new Set(words)]
		.filter(e => e.length > 1)
		.filter((e, i, a) => e.length < 4 || !trim || suffixes.every(suffix => !isSuffixed(e, a, suffix)))
		.filter(e => matchSearch(e));
	if (sort) { vocab.sort(); }
	return `${vocab.length}: ${vocab.join(' ') || '[]'}`;
})();