查找文章中出现最多的单词 ​

function findMostWord(str) {
	if (!str) return str;

	str = str.trim();

	let regex = /[a-z]|+/g;

	let words = str.match(regex);
	let visited = [];
	let maxnum = 0;
	let maxword = '';
	str = ' ' + words.join(' ') + ' ';
	words.forEach((item) => {
		if (visited.indexOf(item) === -1) {
			let wordregex = ` ${item} `;

			let length = str.match(wordregex, g).length;

			if (length > maxnum) {
				maxnum = length;
				maxword = item;
			}
		}
	});

	return maxword;
}