this is the most horrifying Firefox bug I've ever seen to date:
https://codepen.io/WebReflection/pen/WXaeWj?editors=0010

Filed a bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1421260

Argh! Will get it prioritized and fixed.

I saw the bug has been confirmed.
I tested with FF 56-58.beta and it is there: so I suppose it is also in the previous releases.
Hope it will be fixed for the final 58.

In the meantime my ugly workaround is the following one:

class Foo {
    static init() {
        const render = hyperHTML.bind(document.querySelector("foo"));

        const state = {
            items: [
                { id: 1, text: "foo" },
                { id: 2, text: "bar" },
                { id: 3, text: "baz" }
            ],
            selectedItem: 2
        };

        const node = render`
            <select>${
                state.items.map(item => hyperHTML.wire()`
                    <option value="${item.id}">
                        ${item.text}
                    </option>
                `)
            }</select>
        `;
        document.querySelector(`option[value='${state.selectedItem}']`).selected = true;
    }
}

setInterval(Foo.init, 100);

Live example: https://plnkr.co/edit/6Guxg7nEIYPzJmt5IaZR?p=preview

Tested also in my complex use case and it works correctly.

it's a diffing algorithm issue, if you use majinbuu engine instead, everything is fine without needing workarounds.

https://plnkr.co/edit/IgjYDmRx2doychS6zDnw?p=preview

Bug resolved in FF 58.0b8. :)

P.S. No, I am sorry, I see ghosts. It is not resolved. Sorry for the noise.

I am planning to implement domdiff as universal solution for hyperHTML so that current engine will go and majinbuu won't be needed.

That should also, hopefully, solve, this issue forever, even on older FF.

actually ... never mind: https://codepen.io/WebReflection/pen/EbMwwV?editors=0010

this bug affects Vue.js and Preact with keyed elements too ... this is very bad

P.S. @albertosantini if you used wires properly thought, you wouldn't have experienced any of this. You are trashing options every time. It's still a FF bug, but you should never trash nodes when it's possible.

I am planning to implement domdiff as universal solution for hyperHTML so that current engine will go and majinbuu won't be needed.

What is the reason behind this decision?

What is the reason behind this decision?

nobody is writing hyperHTML engines and AFAIK nobody uses hyperhtml-majinbuu but the point is that current default engine doesn't scale in terms of performance and neither does majinbuu.

Instead of having all these hybrid, not fully usable solutions for this or that case, I'd rather use what Vue.js and Preact are using to diff their content (a fork of snabbdom) which apparently performs as good as majinbuu but it scales way more without needing checks on array size and all the caveats one or the other solution has.

On top of that, removing complexity and abstractions with 3rd parts engines, will reduce the library size closer to 4K instead of 5K

in case anyone is curious about engine-less edition of hyperHTML:
#149