SolidJS•15mo ago

Get SSR attribute value when hydrating

Hi guys! The server generates an attribute value for an element and I don't want to re-generate that attribute value on the browser side because it's unnecessary load on the user device. Is it possible to access the to-be-updated element from within the client side component function code? e.g.

const myAttr = createSignal(isServer ? doHeavyCalculationThing() : hydrationEl.dataset.myAttr);

// return JSX using myAttr

const myAttr = createSignal(isServer ? doHeavyCalculationThing() : hydrationEl.dataset.myAttr);

// return JSX using myAttr

I do still need the doHeavyCalculationThing's code to be given to the client as it will need to re-calculate after an interaction. cheers!

6 Replies

thetarnav•15mo ago

might looks at this: https://github.com/lxsmnsyc/solid-use/blob/main/docs/server-value.md

GitHub

solid-use/server-value.md at main · lxsmnsyc/solid-use

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thetarnav•15mo ago

I guess this is what it's for @lxsmnsyc

jimmyjamiejamesjimbob•15mo ago

hey @thetarnav thanks for sending this! helpful little library that - although this'll work, I'm wondering if I could somehow just read the element's attribute since that's already in the document anyway and looking at that library's source, it seems to create a script tag with the data duplicated to get it to the client - for this specific use case, accessing the element to-be-hydrated would be ideal!

thetarnav•15mo ago

ah you certainly can I assume it has to happen in onMount for the ref to be populated otherwise you could use a query selector to get the el since it's already in the dom

jimmyjamiejamesjimbob•15mo ago

function retrieveSsrClass() {
  const el = document.querySelector(`*[data-hk^="${sharedConfig.context?.id}"]`) as HTMLElement;
  if (el == null) {
    return null;
  }

  return el.getAttribute('class');
}

function retrieveSsrClass() {
  const el = document.querySelector(`*[data-hk^="${sharedConfig.context?.id}"]`) as HTMLElement;
  if (el == null) {
    return null;
  }

  return el.getAttribute('class');
}

this is what I ended up doing, seems to work, don't know if it will work for every scenario aha and I'm sure there's a more efficient way of accessing the element, if anyone has any better ideas lmk! - thanks for your help @thetarnav!

lxsmnsyc•15mo ago

This goes beyond an element's attribute, like you can use this for components that do not render an element, directly or indirectly. It can also serialize beyond a string value This one potentially will cause hydration mismatches since I assume you'd want to run it before the element hydrates server-value beats that in every aspect

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Get SSR attribute value when hydrating