Custom Node Help: Convert Fixed Collection Data to API-Compatible Format

Questions
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1

Help with Fixed Collection Data Transformation in Declarative Style

Hi everyone,

I’m currently developing a custom node in the declarative style, as recommended, but I’m struggling with transforming data so that my API endpoint receives it in the expected format.

I have a Fixed Collection like this:

{
    displayName: 'Item Test',
    name: 'itemTest',
    placeholder: 'Add Item Test',
    type: 'fixedCollection',
    default: '',
    typeOptions: {
        multipleValues: true,
    },
    options: [
        {
            name: 'itemValues',
            displayName: 'Item',
            values: [
                {
                    displayName: 'Name',
                    name: 'name',
                    type: 'string',
                    default: 'Name of the Item',
                },
                {
                    displayName: 'Quantity',
                    name: 'quantity',
                    type: 'number',
                    default: '',
                    description: 'Item quantity',
                },
            ],
        },
    ],
}

With this setup, the node output looks like this:

{
  "itemTest": {
    "itemValues": [
      { "name": "Item 1", "quantity": 1 },
      { "name": "Item 2", "quantity": 2 }
    ]
  }
}

However, my API expects the data in this format:

{
  "items": [
    { "name": "Item 1", "quantity": 1 },
    { "name": "Item 2", "quantity": 2 }
  ]
}

Is there a way to transform the structure in declarative mode, or do I need to switch to programmatic mode? Any help or best practices would be greatly appreciated!

Thanks! :blush:

This post was written with the help of AI to improve clarity, as English is not my native language.

2

It looks like your topic is missing some important information. Could you provide the following if applicable.

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3

hello @paulkolle

Can’t say for the syntax ( I’m using the programmatic style in community nodes), but check the resource mapper type.
Node UI elements | n8n Docs