It COmpiles other unknown files

[Zedonboy]

Webpack-server-compiles other sources in node-modules. which bloat app.js
here's my webpack config

const path = require("path")
module.exports = {
    entry: './app.js',
    output: {
        path: path.resolve(__dirname, 'build'),
        filename: 'app.js'
    },
    mode: "development",
    devServer: {
        inline: true,
        port: 8080,
        publicPath: '/build/'
    },
    module: {
        rules: [{
            test: /\.js$/,
            loader: 'babel-loader',
            exclude: /node_modules/,
        }]
    }
}

then i made this call at the Cli webpack-dev-server --watch-poll --progress --colors

here's the output

 Asset     Size  Chunks             Chunk Names
app.js  406 KiB    main  [emitted]  main
Entrypoint main = app.js
[./app.js] 74 bytes {main} [built]
[./kontra.js] 65 KiB {main} [built]
[./node_modules/ansi-regex/index.js] 135 bytes {main} [built]
[./node_modules/html-entities/index.js] 231 bytes {main} [built]
[./node_modules/loglevel/lib/loglevel.js] 7.68 KiB {main} [built]
[./node_modules/sockjs-client/dist/sockjs.js] 177 KiB {main} [built]
[./node_modules/strip-ansi/index.js] 161 bytes {main} [built]
[./node_modules/url/url.js] 22.8 KiB {main} [built]
[./node_modules/webpack-dev-server/client/index.js?http://localhost:8080] (webpack)-dev-server/client?http://localhost:8080 7.78 KiB {main} [built]
[./node_modules/webpack-dev-server/client/overlay.js] (webpack)-dev-server/client/overlay.js 3.58 KiB {main} [built]
[./node_modules/webpack-dev-server/client/socket.js] (webpack)-dev-server/client/socket.js 1.05 KiB {main} [built]
[0] multi (webpack)-dev-server/client?http://localhost:8080 ./app.js 40 bytes {main} [built]
[./node_modules/webpack/hot sync ^\.\/log$] (webpack)/hot sync nonrecursive ^\.\/log$ 170 bytes {main} [built]
[./node_modules/webpack/hot/emitter.js] (webpack)/hot/emitter.js 75 bytes {main} [built]
[./node_modules/webpack/hot/log.js] (webpack)/hot/log.js 1.11 KiB {main} [optional] [built]
    + 12 hidden modules

Whats the problem? what did i get wrong