Add ignore-nullish modifier to x-html and x-text

[willrowe]

This adds an ignore-nullish modifier to x-html and x-text. If the value is set to null or undefined, the currently set HTML/text will remain unchanged.

The main use case for this is to have the initial HTML/text set in the markup on page load. See the updates to the documentation for examples.

[ekwoka]

I like the modifier approach.

I think I'd be more partial to preserve-nullish as opposed to ignore but that's just my opinion.

[willrowe]

@ekwoka

I think I'd be more partial to preserve-nullish as opposed to ignore but that's just my opinion.

preserve-nullish implies that you are preserving a nullish value, which I would find confusing.

[ekwoka]

Yeah....but preserve-on-nullish is too long 😭

[Tim-Wils]

What is the value becomes null again after being set to a value? Shouldn't the value become the original innerHTML again with this modifier?

[willrowe]

@Tim-Wils no, as the name infers, it ignores any nullish values and does not change the HTML/text. It will be most useful on initial state.