undefined value on input and other elements

[PatrickG]

Describe the bug
The value prop behaves differently in various situations.

Suppose we have a variable let value = undefined.

If you use it on an input element with two-way binding <input bind:value />, the value is not set (this is the correct behavior, it got fixed in #3430).
If you use it on an input element like this: <input {value} />, the input elements value property is set to the string 'undefined' (not the attribute).
If you use it on any other element, like: <option {value} />, the value attribute is set to "undefined".

To Reproduce
https://svelte.dev/repl/9a8cf877df9a47948eb0cd3b04ea8372?version=3.19.1

Expected behavior
I think the value attribute (without two-way binding) should behave like the disabled attribute in the repl.

Severity
low

Additional context
You can get around it with <input value={value || ''} />

[Conduitry]

Is this the same as #3569?

[PatrickG]

Not really. Its more about the inconsistency when not using two-way binding vs using two-way binding.

[dgellow]

You can get around it with <input value={value || ''} />

That doesn't work as expected when using <input type="submit value={value || ''} />. That results in a submit button with no text instead of the expected "Submit".

Edit: it's a detail, just worth pointing out that this workaround has some unexpected effect.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.