Migrating from 0.16

1.0.0 is a breaking release. The last published stable version used .eslintrc and shipped JavaScript from src/. This release:

• Is written in TypeScript and ships compiled output from dist/
• Requires Node.js 24+
• Uses ESLint 10 flat config only

Install the beta while 1.0 is in pre-release:

yarn add -D @ekz/packer@beta

ESLint

1. Delete .eslintrc
2. Add eslint.config.js — see ESLint setup
3. Update your lint script to "lint": "npx eslint ."

Node.js

Requires Node.js 24 or later. Add an .nvmrc (for example v24.17) and run nvm use.

Webpack

The public API is unchanged:

const Packer = require('@ekz/packer');

module.exports = Packer.webpack.createApplicationConfiguration();

If you customized webpack via Packer options, review Webpack configuration — defaults may have changed with dependency upgrades.

TypeScript config location

Packer looks for tsconfig.json at the app root. If yours lives in a subdirectory (for example src/main/web/tsconfig.json), either add a root config or set tsconfigPath:

module.exports = Packer.webpack.createApplicationConfiguration({
    tsconfigPath: 'src/main/web/tsconfig.json'
});

Without a discoverable TypeScript config, .tsx is transpiled by Babel instead of ts-loader. Babel can emit development-only jsxDEV calls that crash in production (jsxDEV is not a function). Prefer ts-loader with jsx: react-jsx in your tsconfig.

Dev server

1.0 bundles webpack-dev-server v5 (0.16 used v4). Packer’s built-in defaults are unchanged — port 9000, hot reload, compression, and a CORS header — so apps that never customized devServer need no changes.

If you pass a custom devServer block, update it for v5. See the webpack-dev-server v5 migration guide for the full list.

Scripts

Use npx so CLI binaries resolve from @ekz/packer when it is your only direct dev dependency:

{
    "scripts": {
        "build:dev": "npx webpack --mode=development",
        "build:prod": "npx webpack --mode=production",
        "build:watch": "npx webpack-dev-server --mode=development"
    }
}

Proxy

proxy must be an array in v5 (object keys are no longer accepted):

// 0.16 (v4)
devServer: {
    proxy: {
        '/api': {
            target: 'http://localhost:8080',
            changeOrigin: true
        }
    }
}

// 1.0 (v5)
devServer: {
    proxy: [{
        context: ['/api'],
        target: 'http://localhost:8080',
        changeOrigin: true
    }]
}

HTTPS and HTTP/2

Replace https / http2 with the server option:

devServer: {
    server: {
        type: 'https', // or 'spdy' for HTTP/2
        options: {
            key: './path/to/server.key',
            cert: './path/to/server.crt'
        }
    }
}

Custom middleware

Replace onBeforeSetupMiddleware / onAfterSetupMiddleware with setupMiddlewares:

devServer: {
    setupMiddlewares: (middlewares, devServer) => {
        // add custom middleware before or after defaults
        return middlewares;
    }
}

Custom ESLint rules

Move rule overrides from .eslintrc into eslint.config.js as an additional config object after the Packer spreads. See ESLint.

No ESLint 9 intermediate step

Consumers can go directly from 0.16 to 1.0 flat config. There was no published ESLint 9 transition release.