How to recreate/update gatsby source nodes

I’m creating a couple source nodes with gatby’s sourceNodes API. I noticed that in development mode all nodes are correctly created when the dev server is started, but as I work on my app the nodes become stale due to changes in the data they are reading.

I’m wondering if there’s any API or examples I can see that will show me how to update (or re-create) these source nodes while the dev server is running.

Thanks!

[ryanto]

Ok I think I figured it out, wanted to add it here incase anyone runs into this in the future.

https://www.gatsbyjs.org/docs/creating-a-source-plugin/#option-1-transformation-relationships

An example of a transformation relationship is the gatsby-transformer-remark plugin, which transforms a parent File node’s markdown string into a MarkdownRemark node. The Remark transformer plugin adds its newly created child node as a child of the parent node using the action createParentChildLink. Transformation relationships are used when a new node is completely derived from a single parent node. E.g. the markdown node is derived from the parent File node and wouldn’t ever exist if the parent File node hadn’t been created.

Because all children nodes are derived from their parent, when a parent node is deleted or changed, Gatsby deletes all of the child nodes (and their child nodes, and so on) with the expectation that they’ll be recreated again by transformer plugins. This is done to ensure there are no nodes left over that were derived from older versions of data but shouldn’t exist any longer.

The trick is to use createParentChildLink between your node and the node that represents the file on disk (which you can get from onCreateNode).

Thanks again!

[arryanggaputra]

@ryanto I have similar question with you, and figure out about createParentChildLink but have no clue, can I know how you implement it? Thanks