get identifier() {
    if (typeof identifierCache[this.name] !== "string") {
      const identifier = `${camelize(
        this._container.inflector.singularize(this.name)
      )}Ids`;

      identifierCache[this.name] = identifier;
    }

    return identifierCache[this.name];
  }
@class HasMany
@extends Association
@constructor
@public
@hide