Loop Nodes
- Anthony George
Overview
Use a 
Loop Node when it is necessary to repeat an action or set of actions multiple times.
There are three types of supported looping:
Polling, repeating the same operation multiple times with the same parameters until a desired result is obtained and then generating a single output record. Output results are only generated at the end of the iterations. For example, polling an HTTP API until the results are available.
Accumulation, repeating the same operation multiple times, where each iteration accumulates the progress results and triggers the next iteration with the updated result. Generates a single output record. For example, calling the DB to get the parent record, and repeating with the parent until the root has been reached.
Paging, repeating an operation multiple times with different parameters and generating the next parameters with a set of output records for each iteration of the loop. For example, reading from a paging API, where each iteration gives you the link for the next iteration and a set of output records.
Start Loop and End Loop
Loops consist of a 
Start Loop Action and an 
End Loop Action joined by a loop connector which returns the result of the End Node to the Start Node. Each part of the loop has properties described below.
The key concept of a loop is that the attributes passed into it are available as a passthrough and mapped in attributes. This allows for the original passthrough value to be referenced and if the loop is manipulating the incoming attribute, for example incrementing a number, this is also available. The mapped attributes that are manipulated by the loop are shown with a loop icon, passthrough attributes will be shown with the icon of where they come from for example a calculated action.
Properties Tab - Start Loop
Basic Settings
| Field | Description | Example Value |
|---|---|---|
| Name | The name given to the node and displayed on the canvas. | My Loop |
| End Loop Action | A read-only field that states the end loop node associated with the start loop node. | // The End Loop Node will initially take the name of the Start Loop // Node and prefix it with "end".
|
Output Connection Points
This section has a toolbar with standard buttons. The grid contains a list of all output connection points.
- To add a new output path, in the section toolbar click
Add New to open a new output path and set the expression; see Output Connection Points. - To edit an existing output path, double-click it in the list to open its properties.
- To remove an output path, select one and in the section toolbar click
Delete.
Properties Tab - End Loop
Basic Settings
| Field | Description | Example Value |
|---|---|---|
| Name | The name given to the node and displayed on the canvas. The name will default to the Start Loop name prefixed with end. | End My Loop |
| Output Mode | A read-only field that states the end loop node associated with the start loop node. | // The End Loop Node will initially take the name of the Start Loop // Node and prefix it with "end".
|
| Until Expression | An expression that is checked on each cycle of the loop, and once the expression returns true the loop will end. | // Where myValue is being sent into the End Loop Node on a pipe // called in.
|
| Max Loops | This is a safety net designed to stop infinite loops. The number entered here will stop | //Defaults to 10000 10000 |
Input Connection Points
Can Accept a single 
Driving input connection point.
The grid contains a list of all input connection points and their type.
- To add a new input connection point, in the section toolbar click Add New to open a new input connection point and set its properties; see Input Connection Points.
- To edit an existing input connection point, double-click it in the list to open its properties.
- To remove an input connection point, select one and in the section toolbar click Delete.
Output Connection Points
This section has a toolbar with standard buttons. The grid contains a list of all output connection points.
- To add a new output path, in the section toolbar click Add New to open a new output path and set the expression; see Output Connection Points.
- To edit an existing output path, double-click it in the list to open its properties.
- To remove an output path, select one and in the section toolbar click Delete.
Learn More
For links to all pages in this topic, see Understanding Actionflows.