The Problem⌗

After upgrading svelte-seo to the latest version (1.5.4 at the time of writing this), I encountered this error when trying to run my SvelteKit dev server:

Error while preprocessing /home/casey/dream/node_modules/svelte-seo/index.svelte - Cannot find module './transformers/"application/ld+json">${'
Require stack:
- /home/casey/dream/node_modules/svelte-preprocess/dist/autoProcess.js
- /home/casey/dream/node_modules/svelte-preprocess/dist/index.js
Error while preprocessing /home/casey/dream/node_modules/svelte-seo/index.svelte - Cannot find module './transformers/"application/ld+json">${'
Require stack:
- /home/casey/dream/node_modules/svelte-preprocess/dist/autoProcess.js
- /home/casey/dream/node_modules/svelte-preprocess/dist/index.js

The Fix⌗

The issue turned out to be that my svelte version was too old.

I upgraded svelte to the latest version (svelte ^3.50.1 → ^4.2.7), re-started the dev server, and the issue went away.