[alevans4]

1. The MobX-like functionality is moreso simply a native feature of Vue. All data values are converted into observed values. A render is triggered by changes to data. I believe Evan himself basically said React + MobX = Vue. Using a render function was just a choice. It could just as easily have been written with a template.

2. Again, this was basically just a choice for the example. The spinner could be defined in a module and imported/registered locally. Codepen/JSFiddle just isn't the greatest place for that kind of example.

3. Scoped slots are a way for a component to expose internal data to elements contained in a slot (content thats contained within the component but defined by it's parent). I agree, its initially one of the more confusing concepts in Vue.

[spion]

Ok I think I figured out how to use a template with a slot in the spinner component:

    <div>
    <img v-if="this.status == 'pending'" 
         src="https://media.giphy.com/media/10kTz4r3ishQwU/giphy.gif" />
    <slot v-if="this.status == 'success'" :list="this.data"></slot>
    <div v-if="this.status == 'error'">{{this.error}}</div>
    </div>

Then in the template the option line becomes

    <option v-for="option in data.list" :value="option">{{option}}</option>

Not too bad. Guess I'll have to come up with a new example of what Vue templates can't do now!

[alevans4]

You nailed it :) You could also destructure the passed properties in the scoped slot (scope="{list}") so you could just use "option in list".

[djur]

I wonder if the JS snippets in those attributes is syntax checked at build time or run time.

[alevans4]

Vue templates are compiled into render functions. They are checked when the template is compiled. If you are using a build process, then that would be at build time.

[djur]

Is there any editor support for that? One of the things I like about React + TypeScript is that the JSX is syntax-checked and type-checked in my editor as I type. My understanding is that this is possible because TS has built-in support for JSX.

[alevans4]

Not yet as far as I know.