title: Result is not saved in json
body: <p>I am using <code>scrapy</code> and running this script:</p>
  <pre><code>import scrapy
  from ..items import SizeerItem
  from scrapy.http.request import Request
  
  class SizeerSpiderSpider(scrapy.Spider):
      name = 'sizeer'
      pg = 0
      currentPg = 2
      start_urls = [
          'https://sizeer.lt/moterims'
      ]
  
      def parse(self, response):
          items = SizeerItem()
          pages = response.xpath(&quot;//nav[@class='m-pagination']//span[3]/text()&quot;).extract()
          pages = list(dict.fromkeys(pages))
  
          if self.pg == 0:
              pages = list(int(s) for s in pages[0].split() if s.isdigit())
              self.pg = pages[0]
  
          name = response.xpath(&quot;//div[@class='b-productList_content']//a/@href&quot;).extract()
  
          items['name'] = list(dict.fromkeys(name))
  
          while self.currentPg &lt;= self.pg:
              url = response.request.url + &quot;?sort=default&amp;limit=60&amp;page=&quot; + str(self.currentPg)
              self.currentPg += 1
              yield Request(url, callback=self.parse)
  </code></pre>
  <p>This way:</p>
  <pre><code>scrapy crawl sizeer -s FEED_URI='mydata.json' -s FEED_FORMAT=json
  </code></pre>
  <p>But after that my <code>mydata.json</code> is empty. This is my first time trying to 'play' with it and can't really understand where is the issue.</p>