Bucle

Lo que hace

Iterates over a collection and runs the nodes in the loop body once for each item.

When to use this

Use a Loop when you have a collection of items to process, such as a list of records returned by an API, a list of files, or a list of IDs. The loop runs once per item and stops when the collection is exhausted.

To exit before the collection is exhausted, use Break on condition or a break handle, both described below.

Configuration reference

Campo	Obligatorio	Predeterminado	Descripción
Colección	Sí	Ninguno	Array to iterate over. Enter an expression that resolves to an array, for example $vars.listCustomers1.output.
Paralelo	No	Off	Runs all iterations at the same time instead of one after another. When off, the loop runs sequentially and waits for each iteration to finish before starting the next.
Break on condition	No	Ninguno	Expression that exits the loop early when it becomes true after an iteration completes. This applies to sequential loops.
Show break handle	No	Off	Adds a break handle to the loop so nodes inside the body can exit the loop early. Connect a node's output to the break handle to stop iterating from inside the body.

Nota:

Sequential iteration preserves order and is required for Break on condition to work, since the condition is checked after each iteration completes. Parallel iterations don't run in a guaranteed order.

The loop body

Drag nodes inside the Loop boundary to add them to the body. Nodes in the body can read the current item and iteration, along with any variables in scope outside the loop.

Current item and iteration

Inside the body, reference the loop's progress with these expressions:

• $vars.<loopName>.currentItem is the item for the current iteration. Access its fields with dot notation, for example $vars.loop1.currentItem.id.
• $vars.<loopName>.currentIteration is the current iteration number, starting at 1.

These are available only inside the loop body.

Salida

After all iterations complete, the loop's aggregated results are available at $vars.<loopName>.output. Execution then continues from the node after the loop.

currentItem and currentIteration are not accessible outside the loop body.

Ejemplos

Example 1 — Call an API for each item

The loop iterates over $vars.listCustomers1.output. The loop body contains an HTTP Request node with the URL:

https://api.example.com/customers/{{ $vars.loop1.currentItem.id }}

Example 2 — Build a result array across iterations

A Script node in the loop body returns a value for each item. The loop collects each iteration's result into $vars.loop1.output:

return { id: $vars.loop1.currentItem.id, processed: true };

After the loop, $vars.loop1.output is an array of those results.

Example 3 — Stop early once a match is found

A Decision node in the loop body checks the current item. With Show break handle enabled, the Decision's matching branch connects to the loop's break handle to stop iterating as soon as the match is found.

Problemas comunes

The loop body never runs. The collection is empty or undefined. Check the upstream node's output in the execution trace to confirm the array has items. An empty collection skips the body and continues after the loop.

Break on condition never triggers in a parallel loop. Break on condition is evaluated after each iteration completes in order, so it applies to sequential loops. Turn off Parallel if you need to break on a running condition.

Editing the collection inside the body doesn't change what's iterated. The collection is captured when the loop starts. Modifying the array variable inside the body doesn't change which items are iterated. This is by design.

Páginas relacionadas

• Flujo de control
• Decisión
• Variables and data flow