function cachePush(value) {
      var data = this.data,
          type = typeof value;

      if (type == 'number') {
        data[type][value] = true;
      } else {
        data.set.add(value);
      }
    }
Adds `value` to the cache.

@private
@name push
@memberOf SetCache
@param {*} value The value to cache.