Webpack is not working with Typescript aliases

You have specified path aliases for typescript compiler but you also need to specify aliases for webpack cause webpack resolves modules in it's own way.

So you need to update webpack config is some way like in the following example:

{
...
  resolve: {
    extensions: ['.ts', '.js'],
    alias: {
      '@': path.resolve(__dirname, 'source/lib'),
      '@lib': path.resolve(__dirname, 'source/lib'),
      '@bin': path.resolve(__dirname, 'source/bin')
    }
  }
...
}

@Mikhail Sereniti 's answer would work, but a module allows this to be handled automatically.

I added this:

plugins: [new TsconfigPathsPlugin({
  configFile: './source/tsconfig.json',
  extensions: ['.ts', '.js']
})]

And it worked.

The full code:

const path = require('path');
const webpack = require('webpack');
const nodeExternals = require('webpack-node-externals');
const BundleDeclarationsWebpackPlugin = require('bundle-declarations-webpack-plugin');
const TsconfigPathsPlugin = require('tsconfig-paths-webpack-plugin');


const libConfig = {
    target: 'node',
    mode: 'production',
    // devtool: 'source-map',
    entry: {
        index: './source/lib/index.ts',
    },
    resolve: {
        extensions: ['.ts', '.js'],
        plugins: [new TsconfigPathsPlugin({
            configFile: './source/tsconfig.json',
            extensions: ['.ts', '.js']
        })]
    },
    module: {
        rules: [
            {
                test: /\.ts$/,
                include: path.resolve(__dirname, 'source'),
                use: [
                    {
                        loader: 'ts-loader',
                        options: {
                            compiler: 'ttypescript'
                        }
                    }
                ]
            }
        ]
    },
    plugins: [
        new BundleDeclarationsWebpackPlugin({
            entry: "./source/lib/index.ts",
            outFile: "./index.d.ts"
        })
    ],
    externals: [nodeExternals()],
    output: {
        path: path.resolve(__dirname, 'bundled', 'lib'),
        filename: 'index.js',
        library: 'mongo-cleaner',
        libraryTarget: 'umd',
        globalObject: 'this',
        umdNamedDefine: true,
    }
};

const binConfig = {
    target: 'node',
    mode: 'production',
    // devtool: 'source-map',
    entry: {
        index: './source/bin/index.ts',
    },
    resolve: {
        extensions: ['.ts', '.js'],
        plugins: [new TsconfigPathsPlugin({
            configFile: './source/tsconfig.json',
            extensions: ['.ts', '.js']
        })]
    },
    plugins: [
        new webpack.BannerPlugin({ banner: '#!/usr/bin/env node', raw: true })
    ],
    module: {
        rules: [
            {
                test: /\.ts?$/,
                include: path.resolve(__dirname, 'source'),
                use: [
                    {
                        loader: 'ts-loader',
                        options: {
                            compiler: 'ttypescript'
                        }
                    },
                    {
                        loader: 'shebang-loader'
                    }
                ]
            }
        ]
    },
    externals: [{
        '../lib/index': {
            amd: '../lib/index',
            root: 'mongo-cleaner',
            commonjs: '../lib/index',
            commonjs2: '../lib/index'
        },
    }, nodeExternals()],
    output: {
        path: path.resolve(__dirname, 'bundled', 'bin'),
        filename: 'index.js',
        library: 'mongo-cleaner',
        libraryTarget: 'umd',
        globalObject: 'this',
        umdNamedDefine: true,
    }
};

module.exports = [
    libConfig,
    binConfig
];

EDIT:

I found also another error. I used ttypescript for a similar purpose, but the "plugins" keyword should have been inside the compiler options.

So, even without the TsconfigPathsPlugin thing, by changing the tsconfig.json like this the problem was solved:

{
    "compilerOptions": {
        "moduleResolution": "node",
        "module": "commonjs",
        "target": "ES5",
        "strictNullChecks": true,
        "lib": [
            "ES2021"
        ],
        "outDir": "../dist",
        "sourceMap": true,
        "declaration": true,
        "baseUrl": ".",
        "paths": {
            "@/*": [
                "./lib/*"
            ],
            "@lib/*": [
                "./lib/*"
            ],
            "@bin/*": [
                "./bin/*"
            ]
        },
        "plugins": [
            {
                "transform": "typescript-transform-paths"
            },
            {
                "transform": "typescript-transform-paths",
                "afterDeclarations": true
            }
        ],
    },
    "include": [
        "lib",
        "bin"
    ]
}