code: function eq(index) {
    if (typeof index === 'undefined') return this;
    const length = this.length;
    let returnIndex;
    if (index > length - 1) {
      return new Dom7([]);
    }
    if (index < 0) {
      returnIndex = length + index;
      if (returnIndex < 0) return new Dom7([]);
      return new Dom7([this[returnIndex]]);
    }
    return new Dom7([this[index]]);
  }
docs: eslint-disable-next-line