passing "truthy" values for classes should add them to the output

[mreinstein]

example:

<img></img>


<script type="module">
    import { init, classModule, h } from 'https://cdn.skypack.dev/snabbdom'

    const patch = init([ classModule ])

    const container = document.querySelector('img')

    const vnode = h('img', {
        class: {
          selected: 'true'
        }
      })

    patch(container, vnode)
</script>

When inspecting the DOM, you'll see this:

<img class="selected">

This is because snabbdom internally is not doing a strict compare against true, it'd doing a "truthy" check:

https://github.com/snabbdom/snabbdom/blob/e203f711c60fde72fa391f0a8e927df4a376204b/src/modules/class.ts#L23-L24