Input and Output Mapping in a loop tree

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1

Hi Team,

I am exploring the Loop tree rule in Reels. But unable to find the correct way to map the inputs and outputs. Can you guide me with the same?

For example,

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In the above rule group, in script I am providing,
OP_cars = [
{ make: “BMW”, year: 2023, models: [“A780”, “098”] },
{ make: “Ferrari”, year: 2022, models: [“B765”] },
{ make: “Audi”, year: 2021, models:[“A345”] }
];
I need to loop through the array of objects and get the models as a concatenated list.
Expected output: modelOutput: [“A780”, “098”, “B765”, “A345”]

Below is my mapping

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Thanks,
Lavanya S

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2

@Rocky @Muhammed_Sinan please help

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3

Hi @LavanyaS,

Please find below the detailed explanation that might help you understand the Loop Rule mapping better:

Loop Rule Mapping & Script Explained

:small_blue_diamond: 1. Input Data

In your first SCRIPT node, you define:

OP_cars = [
  { "make": "BMW", "year": 2023, "models": ["A780", "098"] },
  { "make": "Ferrari", "year": 2022, "models": ["B765"] },
  { "make": "Audi", "year": 2021, "models": ["A345"] }
];

This exposes cars as an output key — an array of objects — and becomes the sequence input for the Loop rule.

:small_blue_diamond: 2. Loop Rule Setup

➤ Sequence Configuration:

  • Sequence Field: cars
  • Sequence Type: Array of Objects
  • Output Type: Object (since we’re returning a single object with a key)

➤ Input Field in Loop Rule:

You create:

  • models → this maps to each item’s models field from the cars array

This field will be used in the loop’s script as IP_models.

➤ Output Field in Loop Rule:

You create:

  • concatenatedModel ( → this stores the running array of all models

This will be used as:

  • IP_currentArray in the script (input to loop rule)
  • OP_concatenatedModel as output from the loop script

:small_blue_diamond: 3. Loop Script Rule

Your script inside the loop:

if (!Array.isArray(IP_currentArray)) {
    IP_currentArray = [];
}
IP_currentArray.push(...IP_models);
OP_concatenatedModel = IP_currentArray;

Key explanation:

  • IP_models: contains current iteration’s models
  • IP_currentArray: accumulates models across iterations (comes from conctenatedModel)
  • OP_concatenatedModel: returns the updated array in each loop

:small_blue_diamond: 4. Global Output Mapping

At the end of the loop rule:

  • conctenatedModel (from loop output) is mapped to global key ModelOutput
  • cars from initial script is directly mapped to global output as cars

Final Output

{
  "cars": [
    { "make": "BMW", "year": 2023, "models": ["A780", "098"] },
    { "make": "Ferrari", "year": 2022, "models": ["B765"] },
    { "make": "Audi", "year": 2021, "models": ["A345"] }
  ],
  "ModelOutput": ["A780", "098", "B765", "A345"]
}
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4

Hi @Rocky,
Thank you for the detailed response. I will try this out.

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