# Compile Svelte in Your Head by Tan Li Hau

Original: https://swyx.io/compile-svelte-lihau
Published: 2020-03-02

> Linking to a blogpost I was too lazy to do

Last year, when [I mobilized my network to put together the first NYC Svelte meetup in one week](https://www.swyx.io/writing/starting-dev-community-meetup), I was not even an active Svelte user at the time. I was just a Rich Harris fan and friend.

So of course organizing a meetup involves finding speakers, and when you give yourself one week to find speakers, you can pretty much expect to be one of the speakers 😂

What do I do when I don't know a thing and have to talk about it? I go look at the source code. I had had a lot of success [doing this for React](https://www.swyx.io/speaking/react-hooks/), so I figured I would do this for Svelte. 

Having worked on a [React SFC proposal](https://github.com/sw-yx/react-sfc-proposal), I was super curious exactly how Svelte achieved scoped styles for its components. If you style a `<p>` tag inside a `Parent` component that contains a `Child`, and if there is a `<p>` within that `Child`, somehow the `p` styling from the `Parent` doesn't "bleed" to the `Child`!! It turns out that scoped styling means scoping to the component by attaching a unique classname.

I discovered all this and more by looking at the before-and-after output of the [Svelte REPL](https://svelte.dev/repl/). After all, [Svelte is a language](https://gist.github.com/Rich-Harris/0f910048478c2a6505d1c32185b61934) - and any language has a REPL! As I explored more and more I found that I was able to completely demystify the Svelte template language by being able to predict what the compiled output was going to be.

So I figured I would write a blogpost to organize my thoughts, [like I did for the React one](https://www.netlify.com/blog/2019/03/11/deep-dive-how-do-react-hooks-really-work/) - however the 1 week ran out in a blink and I ended up giving my talk with my slides not even half done.

I wasn't very happy with this and so never posted up my talk at the time. A month later I was visiting Singapore and [got the chance to rerecord the talk](https://www.swyx.io/speaking/svelte-compile-lightning/), but unfortunately the audio was not great.

I never did get around to writing that blogpost, since my curiosity was satiated.

But now, I don't have to :) Li Hau, one of the Svelte maintainers, and a fellow Singaporean who is just better than me in every way, wrote it up!

[You can read Part 1 of his blogpost, Compile Svelte in your Head, on his blog now.](https://lihautan.com/compile-svelte-in-your-head-part-1/)

When you [Learn in Public](https://www.swyx.io/writing/learn-in-public), sometimes you don't even have to write the blogpost, you can just fail a few times and eventually someone will give up waiting for you and just write it instead 😎