For example, in the index page, we need to get the list of post titles from the server (assume we are hosting the app with a server instead of generating static pages), therefore, we need to create a index.json.js file with. Note: The Svelte template uses svelte-preprocess 4.0.0 to support TypeScript. True, because the example is burried here :), @bewards please don't post about unrelated issues. First update the load function in src/routes/index.svelte: Structural typing is a way of relating types based solely on their members, even if you do not explicitly define the type. So here is a snippet that worked for me. page in load functions has been replaced by url and params Error: page in load functions has been replaced by url and params at Object.get (file . For further actions, you may consider blocking this person and/or reporting abuse. What is the effect of cycling on weight loss? It acts like an editor asking for errors against all of your .svelte files. Remember that we defined the JsonValue type to prevent the usage of our localStore store with values that cannot be persisted using JSON.stringify(). Because we're going to store the authentication details (e.g . You can add // @ts-check to the top of a