code: function mergeLtLte(operator, value, fieldMatchers) {
    if (typeof fieldMatchers.$eq !== 'undefined') {
      return; // do nothing
    }
    if (typeof fieldMatchers.$lte !== 'undefined') {
      if (operator === '$lte') {
        if (value < fieldMatchers.$lte) { // more specificity
          fieldMatchers.$lte = value;
        }
      } else { // operator === '$gt'
        if (value <= fieldMatchers.$lte) { // more specificity
          delete fieldMatchers.$lte;
          fieldMatchers.$lt = value;
        }
      }
    } else if (typeof fieldMatchers.$lt !== 'undefined') {
      if (operator === '$lte') {
        if (value < fieldMatchers.$lt) { // more specificity
          delete fieldMatchers.$lt;
          fieldMatchers.$lte = value;
        }
      } else { // operator === '$gt'
        if (value < fieldMatchers.$lt) { // more specificity
          fieldMatchers.$lt = value;
        }
      }
    } else {
      fieldMatchers[operator] = value;
    }
  }
docs: collapse logically equivalent lt/lte values