Example creating an extendable custom input component

[yyx990803]

Sometimes users want to have complicated custom behavior for v-model, or simply 2-way filter like type casting similar to the built-in modifiers.

The custom input component pattern I demonstrated earlier (as mentioned here) is very powerful and can handle all those needs, but it isn't mentioned in the docs.

I think we should either add a paragraph on this at the end of Form Input Bindings (with a tip like "comeback after you understand how components work"), OR add a chapter in the Advanced section of the guide.

[chrisvfritz]

I have an example for transitioning from 2-way filters to a custom input component in the migration guide. @yyx990803 Is that the kind of thing you're thinking of? Either way, I agree it should also be featured elsewhere in the guide.

[yyx990803]

@chrisvfritz ah yeah, that's already very detailed. Maybe an adapted version of that, without assuming a 1.x background.