fuzzaldrin/lib/scorer.js

Fuzzy filtering and string scoring

(function() {
  var PathSeparator, queryIsLastPathSegment;

  PathSeparator = require('path').sep;

  exports.basenameScore = function(string, query, score) {
    var base, depth, index, lastCharacter, segmentCount, slashCount;
    index = string.length - 1;
    while (string[index] === PathSeparator) {
      index--;
    }
    slashCount = 0;
    lastCharacter = index;
    base = null;
    while (index >= 0) {
      if (string[index] === PathSeparator) {
        slashCount++;
        if (base == null) {
          base = string.substring(index + 1, lastCharacter + 1);
        }
      } else if (index === 0) {
        if (lastCharacter < string.length - 1) {
          if (base == null) {
            base = string.substring(0, lastCharacter + 1);
          }
        } else {
          if (base == null) {
            base = string;
          }
        }
      }
      index--;
    }
    if (base === string) {
      score *= 2;
    } else if (base) {
      score += exports.score(base, query);
    }
    segmentCount = slashCount + 1;
    depth = Math.max(1, 10 - segmentCount);
    score *= depth * 0.01;
    return score;
  };

  exports.score = function(string, query) {
    var character, characterScore, indexInQuery, indexInString, lowerCaseIndex, minIndex, queryLength, queryScore, stringLength, totalCharacterScore, upperCaseIndex, _ref;
    if (string === query) {
      return 1;
    }
    if (queryIsLastPathSegment(string, query)) {
      return 1;
    }
    totalCharacterScore = 0;
    queryLength = query.length;
    stringLength = string.length;
    indexInQuery = 0;
    indexInString = 0;
    while (indexInQuery < queryLength) {
      character = query[indexInQuery++];
      lowerCaseIndex = string.indexOf(character.toLowerCase());
      upperCaseIndex = string.indexOf(character.toUpperCase());
      minIndex = Math.min(lowerCaseIndex, upperCaseIndex);
      if (minIndex === -1) {
        minIndex = Math.max(lowerCaseIndex, upperCaseIndex);
      }
      indexInString = minIndex;
      if (indexInString === -1) {
        return 0;
      }
      characterScore = 0.1;
      if (string[indexInString] === character) {
        characterScore += 0.1;
      }
      if (indexInString === 0 || string[indexInString - 1] === PathSeparator) {
        characterScore += 0.8;
      } else if ((_ref = string[indexInString - 1]) === '-' || _ref === '_' || _ref === ' ') {
        characterScore += 0.7;
      }
      string = string.substring(indexInString + 1, stringLength);
      totalCharacterScore += characterScore;
    }
    queryScore = totalCharacterScore / queryLength;
    return ((queryScore * (queryLength / stringLength)) + queryScore) / 2;
  };

  queryIsLastPathSegment = function(string, query) {
    if (string[string.length - query.length - 1] === PathSeparator) {
      return string.lastIndexOf(query) === string.length - query.length;
    }
  };

}).call(this);