FB是未定义的facebook SDK

Question

为什么我不断定义FB。我已经按照https://stackoverflow.com/a/27724488/4414956这样的答案，但我一直无法弄清楚为什么我的FB未定义。

componentDidMount() {
        window.fbAsyncInit = function() {
          FB.init({
            appId      : appId,
            cookie     : true,
            xfbml      : true,
            version    : 'v2.10'
          });
          FB.ui(
      {
        method: 'share_open_graph',
        action_type: 'og.shares',
        display: 'popup',
        action_properties: JSON.stringify({
          object: {
            'og:url': 'some url',
            'og:image': 'some img, must be https',
            'og:title': 'title',
            'og:description': 'description',
          }
        }),
      },
      function(response) {
      }
    );
        (function(d, s, id) {
          var js, fjs = d.getElementsByTagName(s)[0];
          if (d.getElementById(id)) return;
          js = d.createElement(s); js.id = id;
          js.src = "//connect.facebook.net/en_US/sdk.js";
          fjs.parentNode.insertBefore(js, fjs);
        }(document, 'script', 'facebook-jssdk'));
      }
    }