Custom input prop boolean shorthand not working

[benlind]

Reproduction

https://formkit.link/40fd78f583d09a156cee0128be17eac1

Describe the bug

If you have a custom input that accepts a boolean prop, Vue's boolean casting feature does not work. See the reproduction playground.

If I use this:

  <FormKit
    :plugins="[ myPlugin ]"
    type="custom"
    some-boolean
  />

Then the expected value of props.context.someBoolean in the custom component is true. But the actual value is an empty string.

If I instead use the long-hand syntax:

  <FormKit
    :plugins="[ myPlugin ]"
    type="custom"
    :some-boolean="true"
  />

Then props.context.someBoolean is correctly a true boolean.

Environment

• OS: Web (MacOS)
• Browser Chrome
• Version 0.17

[justin-schroeder]

This is true — unfortunately we currently don’t have a great way to make this work "exactly" like vue, however in our own internal inputs we use the undefine utility which converts the prop to either true or undefined — in most cases undefined is actually preferable since it prevents an attribute by the same name from rendering if directly assigned.

For example: https://formkit.link/5e2b7df4f9b28dbf95910440c393884a

[benlind]

undefined works for me, thanks! It is indeed an awkward situation, to have to document this behavior in my codebase so future plugin devs know to use that utility. I'm tempted to ask you to make this the default. :)