How to remove all accents in Vietnamese string | Xóa dấu trong tiếng Việt làm slug hoặc để tìm kiếm

remove_accents_vietnamese.js

const removeAccents = (function () {
  const letters1 = 'ÀÁÂÃÈÉÊÌÍÒÓÔÕÙÚĂĐĨŨƠàáâãèéêìíòóôõùúăđĩũơƯĂẠẢẤẦẨẪẬẮẰẲẴẶẸẺẼỀỀỂưăạảấầẩẫậắằẳẵặẹẻẽềềểếỄỆỈỊỌỎỐỒỔỖỘỚỜỞỠỢỤỦỨỪễệỉịọỏốồổỗộớờởỡợụủứừỬỮỰỲỴÝỶỸửữựỳỵỷỹý'
  const letters2 = 'AAAAEEEIIOOOOUUADIUOaaaaeeeiioooouuadiuoUAAAAAAAAAAAAAEEEEEEuaaaaaaaaaaaaaeeeeeeeEEIIOOOOOOOOOOOOUUUUeeiioooooooooooouuuuUUUYYYYYuuuyyyyy'
  const patternLetters = new RegExp('[' + letters1 + ']', 'g')
  const lookupLetters = {}

  letters1.split('').forEach(function (letter, i) {
    lookupLetters[letter] = letters2[i]
  })

  const letterTranslator = function (match) {
    return lookupLetters[match] || match
  }

  return function removeAccents (input) {
    return input.replace(patternLetters, letterTranslator)
  }
})()

export const removeAccents = (function () {
  const letters1 = 'ÁÀẢÃẠĂẮẰẲẴẶÂẤẦẨẪẬĐÉÈẺẼẸÊẾỀỂỄỆÍÌỈĨỊÓÒỎÕỌÔỐỒỔỖỘƠỚỜỞỠỢÚÙỦŨỤƯỨỪỬỮỰÝỲỶỸỴáàảãạăắằẳẵặâấầẩẫậđéèẻẽẹêếềểễệíìỉĩịóòỏõọôốồổỗộơớờởỡợúùủũụưứừửữựýỳỷỹỵ'
  const letters2 = 'AAAAAAAAAAAAAAAAADEEEEEEEEEEEIIIIIOOOOOOOOOOOOOOOOOUUUUUUUUUUUYYYYYaaaaaaaaaaaaaaaaadeeeeeeeeeeeiiiiiooooooooooooooooouuuuuuuuuuuyyyyy'
  const patternLetters = new RegExp('[' + letters1 + ']', 'g')
  const lookupLetters = {}

  letters1.split('').forEach(function (letter, i) {
    lookupLetters[letter] = letters2[i]
  })

  const letterTranslator = function (match) {
    return lookupLetters[match] || match
  }

  return function removeAccents (input) {
    return input.replace(patternLetters, letterTranslator)
  }
})()