Uncaught SyntaxError in Theme Extension File

[main55]

Hi! I'm new to Shopify development, so this is probably a simple question. I made a shopify app that has a working front-end, back-end, and a theme extension (page widget). So it's structured something like this:

extensions
   page-widget
       assets
           block.js
       blocks
             block.liquid
       shopify.theme.extension.toml
web
    package.json
    frontend
        package.json
package.json

The block.js file is linked to the block.liquid file in the liquid file schema.

However when I run my app locally, and open the extension in my development store, I get the "Uncaught SyntaxError: Cannot use import statement outside a module" error on my block.js file because I have an import statement there: 

import { useAppQuery } from "../../../web/frontend/hooks";

 I have 3 package.json files, and each has "theme": "module", so I'm not sure what else to try? It's only getting triggered in the block.js file and not any of the other .js files I have...