Function checkAnagramMap

String/CheckAnagram.js:41–73

(str1, str2)

 * @example - checkAnagramMap('Eleven plus two', 'Twelve plus one') => true
 */
const checkAnagramMap = (str1, str2) => {
  // check that inputs are strings.
  if (typeof str1 !== 'string' || typeof str2 !== 'string') {
    throw new TypeError('Both arguments should be strings.')
  }

  // If both strings have not same lengths then they can not be anagram.
  if (str1.length !== str2.length) {
    return false
  }

  const str1List = Array.from(str1.toUpperCase()) // str1 to array

  // get the occurrences of str1 characters by using HashMap
  const str1Occurs = str1List.reduce(
    (map, char) => map.set(char, map.get(char) + 1 || 1),
    new Map()
  )

  for (const char of str2.toUpperCase()) {
    // if char has not exist to the map it's return false
    if (!str1Occurs.has(char)) {
      return false
    }

    let getCharCount = str1Occurs.get(char)
    str1Occurs.set(char, --getCharCount)

    getCharCount === 0 && str1Occurs.delete(char)
  }

  return true
}

export { checkAnagramRegex, checkAnagramMap }