Attempting to count hyphens in my note

[CodyBontecou]

I'd like to count the number of listen items (lines starting with -) within my note.

I've attempted the following

let page = dv.current().file.path;
page
.where(p => p.content.startsWith('-'))
  .length
  .then(count => dv.span(`Number of list items: ${count}`));

With no luck. Is something like this possible with dataviewjs?