Hello there, fellow Svelte enthusiasts!
Today, we'll dive into the world of Svelte transitions, exploring how to create smooth and engaging animations in your web applications.

We can make more appealing user interfaces by gracefully transitioning elements into and out of the DOM. Svelte makes this very easy with the transition directive.

Transition functions can accept parameters. We can replace the fade transition with fly and apply it to our paragraph along with some options.

Instead of the transition directive, an element can have an in or an out directive, or both togethe

The svelte/transition module has a handful of built-in transitions, but it's very easy to create your own.

While you should generally use CSS for transitions as much as possible, there are some effects that can't be achieved without JavaScript, such as a typewriter effect:

It can be useful to know when transitions are beginning and ending. Svelte dispatches events that you can listen to like any other DOM event:

Ordinarily, transitions will only play on elements when their direct containing block is added or destroyed. In the example here, toggling the visibility of the entire list does not apply transitions to individual list elements.

Instead, we'd like transitions to not only play when individual items are added and removed with the slider but also when we toggle the checkbox.

We can achieve this with a global transition, which plays when any block containing the transitions is added or removed:

Key blocks destroy and recreate their contents when the value of an expression changes. This is useful if you want an element to play its transition whenever a value changes instead of only when the element enters or leaves the DOM.

Here, for example, we'd like to play the typewriter transition from transition.js whenever the loading message, i.e. i changes. We achieve that by wrapping the p element in a key block.

A particularly powerful feature of Svelte's transition engine is the ability to defer transitions, so that they can be coordinated between multiple elements.

Take this pair of todo lists, in which toggling a todo sends it to the opposite list. In the real world, objects don't behave like that — instead of disappearing and reappearing in another place, they move through a series of intermediate positions.

Using motion can go a long way towards helping users understand what's happening in your app.

We can achieve this effect using the crossfade function, as seen in transition.js, which creates a pair of transitions called send and receive. When an element is 'sent', it looks for a corresponding element being 'received', and generates a transition that transforms the element to its counterpart's position and fades it out. When an element is 'received', the reverse happens. If there is no counterpart, the fallback transition is used.