Add null to composite from project

[damomoyu]

I used a script (autosway),
I noticed that he created only one null in the project.
How can I achieve this effect?

[damomoyu]

Effect of script:

I generated 10 "nulls" in "comp 1" through autosway, and the project shows that nulls have been used 10 times,

I generated 15 "nulls" in "comp 2" through autosway, and null was used 25 times in the project.

[Mathias Moehl]

Say you create two null layers (let's call them LA and LB). This also creates two project items (let's call them PA and PB).

Now you can set the source of LB to PA and then delete PB from the project.

[damomoyu]

How can I set the source of LB to PA?

[damomoyu]

I checked the document, but I still can't set

[Mathias Moehl · Accepted solution]

Have you tried the replaceSource function?

https://ae-scripting.docsforadobe.dev/layers/avlayer/#avlayer-replacesource