September 22nd, 2021 × #react#svelte#javascript

From React To SvelteKit

Scott rewrote his Level Up Tutorials site from React to SvelteKit and discusses his experience with the transition.


In this episode of Syntax, Scott talks with Wes about moving Level Up Tutorials from React to SvelteKit — why he did it, how, benefits, things to watch out for, and more!

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Show Notes

07:28 - Thoughts

  • Apples to oranges, so unfortunately, no super legit ability to compare.
    • SvelteKit isn't analogous with a custom React setup that uses CSR
      • SSR is usually going to be faster - we can ship less JS
      • Some big things changed beyond React → SvelteKit
      • HLS starts grabbing chunks immediately, so it's hard to get accurate load time and transfer.
  • Whole conversion took a couple of months.
  • Hardest part was making UI choices and changes, straight-up converting components one by one wasn't actually that tough

16:14 - Converting React components to Svelte

  • useState becomes just a straight-up variable
  • Graphql calls were hooks now just imported generated functions
  • Remove extranous fragments
  • Convert {things && } to {#if thing}{/if}
  • <component hello={hello} /> becomes <component {hello} />

24:06 - Spark joys

  • State
    • Our checkout flow became way more transparent, way easier with Svelte stores
  • Render flow
    • Was never something we needed to really think about. Didn't think about memoizing, or worrying about too many renders down the line, just never needed to
  • Overall developer experience
    • It's honestly a joy to work in and I don't want to go back
  • Making a library
  • Creating a sitemap was extremely easy, because of server-side routes. file.returnformat.ts ie sitemap.xml.ts
  • CSS without a css-in-js library for scoping is a dream. CSS props are now 100% via CSS variables using the https://svelte.dev/docs#style_props
  • Animations are all done with Svelte's internal animations lib

32:45 - Hosting

  • adapter-node
  • Hosted on Render as a straight-up node process $7/m for more than enough RAM and CPU,
  • Lots of other options for static, Vercel, workers whatever, I like having just a straight-up node app you can host anywhere

35:50 - Things to do

  • Admin tools

37:00 - Challenges

  • ESM is not always smooth sailin
    • Import has from 'lodash/has' didn't working in dev, but import has from 'lodash/has.js' didn't work in prod.
      • Solution was to use lodash.has as the dependency
      • Apollo included all React as a dep unless you import from @core
  • TS is great, but there was once where I wanted to define the entire props ts object for a spread prop, but was not possible
  • Drag animations


42:46 - Wes' questions

  • What about the ecosystem?
  • What about forms + DOM data?
  • Serverless functions?
  • Do you always bind to state? Or just access directly?
formData = writable({
  title: "yo"


<input bind:value={formData.title} />


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