Loop

The Loop block is a container that executes blocks repeatedly. Iterate over collections, repeat operations a fixed number of times, or continue while a condition is met.

Loop blocks are container nodes that hold other blocks inside them. The contained blocks execute multiple times based on your configuration.

Configuration Options

Loop Type

Choose between four types of loops:

For Loop (Iterations) - A numeric loop that executes a fixed number of times:

Use this when you need to repeat an operation a specific number of times.

Example: Run 5 times
- Iteration 1
- Iteration 2
- Iteration 3
- Iteration 4
- Iteration 5

ForEach Loop (Collection) - A collection-based loop that iterates over each item in an array or object:

Use this when you need to process a collection of items.

Example: Process ["apple", "banana", "orange"]
- Iteration 1: Process "apple"
- Iteration 2: Process "banana"
- Iteration 3: Process "orange"

While Loop (Condition-based) - Continues executing while a condition evaluates to true:

Use this when you need to loop until a specific condition is met. The condition is checked before each iteration.

Example: While {"<variable.i>"} < 10
- Check condition → Execute if true
- Inside loop: Increment {"<variable.i>"}
- Inside loop: Variables assigns i = {"<variable.i>"} + 1
- Check condition → Execute if true
- Check condition → Exit if false

Do-While Loop (Condition-based) - Executes at least once, then continues while a condition is true:

Use this when you need to execute at least once, then loop until a condition is met. The condition is checked after each iteration.

Example: Do-while {"<variable.i>"} < 10
- Execute blocks
- Inside loop: Increment {"<variable.i>"}
- Inside loop: Variables assigns i = {"<variable.i>"} + 1
- Check condition → Continue if true
- Check condition → Exit if false

How to Use Loops

Creating a Loop

Drag a Loop block from the toolbar onto your canvas
Configure the loop type and parameters
Drag other blocks inside the loop container
Connect the blocks as needed

Referencing Loop Data

There's an important distinction between referencing loop data from inside vs outside the loop:

Inside the loop, use <loop.> references to access the current iteration context:

<loop.index>: Current iteration number (0-based)
<loop.currentItem>: Current item being processed (forEach only)
<loop.items>: Full collection being iterated (forEach only)

// Inside a Function block within the loop
const idx = <loop.index>;           // 0, 1, 2, ...
const item = <loop.currentItem>;    // Current item

These references are only available for blocks inside the loop container. They give you access to the current iteration's context.

Outside the loop (after it completes), reference the loop block by its name to access aggregated results:

<LoopBlockName.results>: Array of results from all iterations

// If your loop block is named "Process Items"
const allResults = <processitems.results>;
// Returns: [result1, result2, result3, ...]

After the loop completes, use the loop's block name (not loop.) to access the collected results. The block name is normalized (lowercase, no spaces).

Example Use Cases

Processing API Results - ForEach loop processes customer records from an API

API (Fetch) → Loop (ForEach) → Agent (Analyze) → Function (Store)

Iterative Content Generation - For loop generates multiple content variations

Loop (5x) → Agent (Generate) → Evaluator (Score) → Function (Select Best)

Counter with While Loop - While loop processes items with counter

Variables (i=0) → Loop (While i<10) → Agent (Process) → Variables (i++)

Advanced Features

Limitations

Container blocks (Loops and Parallels) cannot be nested inside each other. This means:

You cannot place a Loop block inside another Loop block
You cannot place a Parallel block inside a Loop block
You cannot place any container block inside another container block

If you need multi-dimensional iteration, consider restructuring your workflow to use sequential loops or process data in stages.

Loops execute sequentially, not in parallel. If you need concurrent execution, use the Parallel block instead.

Inputs and Outputs

Loop Type: Choose between 'for', 'forEach', 'while', or 'doWhile'
Iterations: Number of times to execute (for loops)
Collection: Array or object to iterate over (forEach loops)
Condition: Boolean expression to evaluate (while/do-while loops)

Available inside the loop only:

<loop.index>: Current iteration number (0-based)
<loop.currentItem>: Current item being processed (forEach only)
<loop.items>: Full collection (forEach only)

<blockname.results>: Array of all iteration results (accessed via block name)
Structure: Results maintain iteration order
Access: Available in blocks after the loop completes

Best Practices

Set reasonable limits: Keep iteration counts reasonable to avoid long execution times
Use ForEach for collections: When processing arrays or objects, use ForEach instead of For loops
Handle errors gracefully: Consider adding error handling inside loops for robust workflows

Loop

On this page