This extension only supports the Stimulus v1 old syntax and NOT the new syntax introduced in v2
https://github.com/tejanium/vscode-stimulusjs/issues/103 https://github.com/hotwired/stimulus/issues/342#issuecomment-816184627
This extension provides Completion, Definition, and Diagnostic of your Stimulus' Controllers/Targets/Actions on your HTML markup (or ERB).
Completion
Definition
Diagnostic