code: function match_bitapScore_(e, x) {
      var accuracy = e / pattern.length;
      var proximity = Math.abs(loc - x);
      if (!self.Match_Distance) {
        // Dodge divide by zero error.
        return proximity ? 1.0 : accuracy;
      }
      return accuracy + (proximity / self.Match_Distance);
    }
docs: 'this' becomes 'window' in a closure. 
  Compute and return the score for a match with e errors and x location.
  Accesses loc and pattern through being a closure.
  @param {number} e Number of errors in match.
  @param {number} x Location of match.
  @return {number} Overall score for match (0.0 = good, 1.0 = bad).
  @private