title: React Native: Displaying multiple images through map
body: <p>I have an object which I passed through another route and I want to display the images it holds. I am checking if I received the props like this: </p>
  
  <pre><code>  checkParams = () =&gt; {
      let params = this.props.navigation.state.params;
      console.log("comments.js params= ", params);
  
      if (params.photoId) {
  
        this.setState({
          photoId: params.photoId,
          REAL: params.REAL,
          FAKE: params.FAKE,
          url: params.url,
          author: params.author,
          posted: params.posted,
          caption: params.caption
        });
  
        this.fetchComments(params.photoId);
      }
    };
  </code></pre>
  
  <p>console.log("comments.js params= ", params) gives:</p>
  
  <pre><code>comments.js params=  Object {
    "FAKE": 0,
    "REAL": 0,
    "author": "USER",
    "caption": "CAPTION",
    "photoId": "47d5-9420-c99a-7459-640d",
    "posted": "72 minutes ago",
    "url": Array [
      Object {
        "url": "https://firebasestorage.googleapis.com/v0/b/...someURL...",
      },
      Object {
        "url": "https://firebasestorage.googleapis.com/v0/b/...someURL...",
      },
      Object {
        "url": "https://firebasestorage.googleapis.com/v0/b/...someURL...",
      },
      Object {
        "url": "https://firebasestorage.googleapis.com/v0/b/...someURL...",
      },
    ],
  }
  </code></pre>
  
  <p>To display all the "url", I am doing this:</p>
  
  <pre><code>          {
              (this.state.url).map(photoItem =&gt; (
                &lt;Image 
                  source={{ uri: photoItem.url }}
                /&gt;
              ))
            }
  </code></pre>
  
  <p>However, I keep getting this Error:</p>
  
  <pre><code>TypeError: undefined is not an object (evaluating 'this.state.url.map)
  </code></pre>
  
  <p>I don't understand what I am doing wrong.</p>