Undefined JSON Property in Code Node Despite Provided Image URL and Alt Text

Based on the troubleshooting guides for Code nodes, one common cause for this behavior is that the data you return (or reference) isn’t adhering to the expected data structure. In n8n, every node’s output should be an array of objects, each with a json key that maps to an object.

Here are some steps and tips you can follow:

1. Verify the Input Data Structure
   Make sure that when you reference your image URL and alt text you are using the keys exactly as they appear in the input. For example, if your input is coming from a previous node as:

   JAVASCRIPTCopied
   {
     "imageURL": "https://example.com/myimage.png",
     "imageAlt": "My image description"
   }

   Make sure that your code correctly accesses these keys (i.e., item.json.imageURL and item.json.imageAlt). A mismatch in key names or case would result in an undefined value.

2. Return the Expected Structure
   Even if your variables are valid, if your node code doesn’t return them in the proper format, the output may appear incorrect. Double-check your return statement. It should look like this:

   JAVASCRIPTCopied
   const items = $input.all();
   
   const newItems = items.map(item => ({
     json: {
       // ensure you're using the correct key names
       imageURL: item.json.imageURL,
       imageAlt: item.json.imageAlt,
       // your other data goes here
     }
   }));
   
   return newItems;

   Make sure that you’re not accidentally returning something like an array for a field that should be an object, or vice versa.

3. Debug with Logs
   You may also find it helpful to log the incoming data or inspect the items array. For example, you can temporarily add:

   JAVASCRIPTCopied
   console.log($input.all());

   Then check the console logs in the n8n execution to verify the keys and their values.

4. Check Data Flow and Expression References
   If you’re using expressions or referencing data from previous nodes, ensure that the nodes are executed in the proper order so that the required data exists. Sometimes the error might show up if the node referenced by the expression hasn’t executed yet.

Following these checkpoints should help you ensure that the image data (URL and alt) are correctly passed to the output JSON, avoiding the undefined fields error.