Either

The Either operator: ? can be used to provide fallback values.

Only dynamic values (attributes and state) are subject to truthiness checks; Static values (defined using let in a template) are never (even if they are false).

       Does this exist?
       and is it truthy?
         /  \
        /    \
       yes   no -------+
        |              |
        V              V
text state.value ? "default"

Example

This will always use the static value, and print false:

text  false ? "hello"

However

text  state.maybe_false ? "hello"

Would print hello if maybe_false is any of the values in the fallback table:

Fallback table

These values causes fallback.

• null
• 0
• ""
• []
• {}
• false

This means that any state or attribute value that resolves to a value listed above will use the fallback.