Webpack does not create or update index.asset.php file in build folder

I could not reproduce the issue, however bear in mind that despite

This is a collection of reusable scripts tailored for WordPress development.

initial sentence in package description, @wordpress/scripts are primarily meant for block development, as block.json are scanned to find entry points. You can also provide entry points yourself, by specifying extra parameter for entry or if your folder is named src. It may depend how your scss is imported (probably from javascript), that in development phase js is created for the purpose of injecting css into the DOM and that is normal. Try invoking build to see if js files disappear.

When I need something that is not block related, I usually set up webpack myself, not relying on @wordpress/scripts. You can as well have several webpack configs in your project and invoking webpack directly and providing specific config as parameter. This also speeds compilation, as I do not compile everything each time, but project is split into chunks. See example below:

  "dependencies": {
    "@fontsource/red-hat-display": "^4.5.11",
    "@wordpress/scripts": "^24.6.0",
    "accordion-js": "^3.3.2",
    "hamburgers": "^1.2.1",
    "micromodal": "^0.4.10"
  "scripts": {
    "viewmodal_development": "webpack --mode=development --watch --config ./webpack-viewmodal.config.js",
    "viewmodal_production": "webpack --mode=production --node-env production --config ./webpack-viewmodal.config.js",
    "blocks_build": "wp-scripts build --webpack-src-dir=./src/blocks",
    "blocks_start": "wp-scripts start --webpack-src-dir=./src/blocks",
    "blocks_hot": "wp-scripts start --webpack-src-dir=./src/blocks --hot",
    "packages-update": "wp-scripts packages-update"

If you need, you can as well add script configuration to invoke more than one task from above, using package concurrently or similar.

EDIT: if you only need scss compiled, I would set up standalone scss compiler, as it is faster than node compilers and setup a task in your editor/IDE – I use VSCode and I added this to tasks.json for compiling scss:

            "label": "sassify build",
            "type": "shell",
            "group": "build",
            "command": "sass",
            "windows": {
                "command": "sass src\\hamburger\\slider.scss assets\\css\\hamburger.css"
            "options": {
                "env": {
                    "PATH": "C:/Noinstall Programs/dart-sass"
            "runOptions": {
                "instanceLimit": 1