From 70d05287c6197ee0be0e80082d439b81089fee83 Mon Sep 17 00:00:00 2001 From: Deborah Barnard Date: Tue, 13 Feb 2024 12:53:53 +0000 Subject: [PATCH] add diagram to errors page --- .../data-mapping/data-item-linking/item-linking-errors.md | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/docs/data/data-mapping/data-item-linking/item-linking-errors.md b/docs/data/data-mapping/data-item-linking/item-linking-errors.md index aadbe4538..be6e6727b 100644 --- a/docs/data/data-mapping/data-item-linking/item-linking-errors.md +++ b/docs/data/data-mapping/data-item-linking/item-linking-errors.md @@ -50,6 +50,11 @@ Refer to [Item linking concepts](/data/data-mapping/data-item-linking/item-linki When using expressions, you can reference data from any previous node. This doesn't have to be the node just before: it can be any previous node in the chain. When referencing nodes further back, you use the expression syntax `$(node_name).item`. Refer to [Mapping in expressions](/data/data-mapping/data-mapping-expressions/) for more information on using this expression. +
+![A diagram showing the threads linking multiple items back through a workflow](/_images/data/data-mapping/data-item-linking/item-linking-multiple-lines.png) +
Diagram of threads for different items. Due to the item linking, you can get the actor for each movie using `$('Get famous movie actors).item`.
+
+ Since the previous node can have multiple items in it, n8n needs to know which one to use. When using `.item`, n8n figures this out for you behind the scenes. Refer to [Item linking concepts](/data/data-mapping/data-item-linking/item-linking-concepts/) for detailed information on how this works. `.item` fails if information is missing. To figure out which item to use, n8n maintains a thread back through the workflow's nodes for each item. For a given item, this thread tells n8n which items in previous nodes generated it. To find the matching item in a given previous node, n8n follows this thread back until it reaches the node in question.