Error in solution for "2.3. Add a dashboard item"

[ronikarjalainen]

Hi,

The assignment has us create a dashboard item, with optional size prop, that should default to 1. That should be reflected in the size of the displayed element.

This is the solution provided: dashboard_item.js
And it's used like this in the Dashboard: dashboard.xml

However, if the prop isn't provided, this is what appears:
<div class="card m-2 border-dark" style="width: NaNrem;"><div class="card-body">some content </div></div>

It looks like I'm not imagining this since it appears to be included in the relevant screenshot as well:

https://www.odoo.com/documentation/18.0/_images/dashboard_item.png

If the elements containing "some content" truly were 18rem wide, they'd be about half of what the element containing "I love milk" is.

I solved it myself by adding setup() in DashboardItem:
setup() { this.size = 1; if(this.props.size && this.props.size > 0) { this.size = this.props.size; } }

And adjusting line 5 in dashboard_item.xml:
<div class="card d-inline-block m-2" t-attf-style="width: {{18*size}}rem;">

Is there a way to make it work with the default value for the size prop though?