Loop

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Enabling Loop

To enable looping for a step:

1. Click the step’s options menu (⋮)
2. Click Add Loop
3. Enter a loop expression that determines how the step iterates

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Loop Expression

• A JavaScript expression that returns the next item to process
• Returns null, undefined, or false to terminate the loop
• Has access to special variables:
  • index: Current iteration number (starts at 0)
  • item: Current value being processed

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Loop Output

• When loop is enabled, the step’s output becomes an array
• Each array element contains the output from one iteration
• Output array maintains the order of processing

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Loop Expression Rules

• Return one item at a time from the array: return items[index];
• Never return the full array (causes infinite loop)

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Accessing Output

When a step has looping enabled, its output becomes an array containing results from each iteration:

const results = modelStep.output.map((item) => item.message);

When accessing the output of a looped step in code steps, you must use array methods like map() to access individual iteration results.

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Loop Termination

Loop stops when the expression returns null, undefined, or false.

Array bounds automatically handle termination:

return items[index]; // Returns undefined when index >= length

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Examples

Here are some practical examples demonstrating how to use loops in your workflows:

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Parallel API Requests

Process multiple API endpoints simultaneously:

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File Batch Processing

Process multiple files with consistent logic:

This eliminates the need for separate model steps for each file.

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Remove Loop

To remove a loop from a step:

1. Click the step’s options menu (⋮)
2. Click Remove Loop