Create Vietnamese slug from string - Javascript

vietnamese-slug.js

function slugify(string){
	const a = 'àáäâãåăæąçćčđďèéěėëêęğǵḧìíïîįłḿǹńňñòóöôœøṕŕřßşśšșťțùúüûǘůűūųẃẍÿýźžż·/_,:;'
	const b = 'aaaaaaaaacccddeeeeeeegghiiiiilmnnnnooooooprrsssssttuuuuuuuuuwxyyzzz------'
	const p = new RegExp(a.split('').join('|'), 'g')
	return string.toString().toLowerCase()
	.replace(/á|à|ả|ạ|ã|ă|ắ|ằ|ẳ|ẵ|ặ|â|ấ|ầ|ẩ|ẫ|ậ/gi, 'a')
	.replace(/é|è|ẻ|ẽ|ẹ|ê|ế|ề|ể|ễ|ệ/gi, 'e')
	.replace(/i|í|ì|ỉ|ĩ|ị/gi, 'i')
	.replace(/ó|ò|ỏ|õ|ọ|ô|ố|ồ|ổ|ỗ|ộ|ơ|ớ|ờ|ở|ỡ|ợ/gi, 'o')
	.replace(/ú|ù|ủ|ũ|ụ|ư|ứ|ừ|ử|ữ|ự/gi, 'u')
	.replace(/ý|ỳ|ỷ|ỹ|ỵ/gi, 'y')
	.replace(/đ/gi, 'd')
	.replace(/\s+/g, '-') 
	.replace(p, c => b.charAt(a.indexOf(c)))
	.replace(/&/g, '-and-')
	.replace(/[^\w\-]+/g, '')
	.replace(/\-\-+/g, '-')
	.replace(/^-+/, '')
	.replace(/-+$/, '')
}

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