Trigger `did-update` lifecycle modifier on reload

[nwhittaker]

Is it possible to trigger the did-update lifecycle modifier on reload?

Consider a case where @user takes a few seconds to populate:

<div {{did-update this.createThumbnail @user}}>
    <img src={{this.thumbnailSrc}} />
</div>

On the first render, the thumbnail is created when @user is populated. However, if I edit only this template, and hot-load re-renders the template, I'm left seeing a broken image because this.createThumbnail does not run for the updated template.

[lifeart]

Hi @nwhittaker, nope, because during hot-reload we don't "rerender" component, we removing it, and applying back (count it as a new render, not update)

For hot-reload case only did-insert modifier should work

[nwhittaker]

...during hot-reload we don't "rerender" component, we removing it, and applying back (count it as a new render, not update)

I guess I'm mainly wondering if there's a way to restore the component's previous state? I was thinking replaying did-update would be an easy-ish way to do that.

I realize there are other use-cases where this may not be the "happy path", though. And the complexity of the implementation could easily outweigh the value.

Thanks for the consideration.

[lifeart]

component state is quite complex thing (except pure components or stateless), we have to track arguments-based state change and event-based (and DOM events may bubble to component from child components)

in short: nope it's likely impossible for generic ember/glimmer components

but, it's possible to implement if you use your own component manager, you could keep component state as not-related to component instance object and reassign it to new component instance

a-la react hooks style (https://github.com/lifeart/hooked-components)

also, it's possible to keep component state, if global state used for it (redux, etc)