string-similarity.js

/**
 * Calculate similarity between two strings
 * @param {string} str1 First string to match
 * @param {string} str2 Second string to match
 * @param {number} [substringLength=2] Optional. Length of substring to be used in calculating similarity. Default 2.
 * @param {boolean} [caseSensitive=false] Optional. Whether you want to consider case in string matching. Default false;
 * @returns Number between 0 and 1, with 0 being a low match score.
 */
var stringSimilarity = function (str1, str2, substringLength, caseSensitive) {
  if (substringLength === void 0) {
    substringLength = 2;
  }
  if (caseSensitive === void 0) {
    caseSensitive = false;
  }
  if (!caseSensitive) {
    str1 = str1.toLowerCase();
    str2 = str2.toLowerCase();
  }
  if (str1.length < substringLength || str2.length < substringLength) return 0;
  var map = new Map();
  for (var i = 0; i < str1.length - (substringLength - 1); i++) {
    var substr1 = str1.substr(i, substringLength);
    map.set(substr1, map.has(substr1) ? map.get(substr1) + 1 : 1);
  }
  var match = 0;
  for (var j = 0; j < str2.length - (substringLength - 1); j++) {
    var substr2 = str2.substr(j, substringLength);
    var count = map.has(substr2) ? map.get(substr2) : 0;
    if (count > 0) {
      map.set(substr2, count - 1);
      match++;
    }
  }
  return (match * 2) / (str1.length + str2.length - (substringLength - 1) * 2);
};

export { stringSimilarity };