[Bug]: Struggling with nestjs

[MIreland]

System Info

  System:
    OS: macOS 14.6.1
    CPU: (10) arm64 Apple M1 Max
    Memory: 1.20 GB / 32.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 20.18.0 - ~/.nvm/versions/node/v20.18.0/bin/node
    npm: 10.8.2 - ~/.nvm/versions/node/v20.18.0/bin/npm
    pnpm: 9.12.3 - ~/.nvm/versions/node/v20.18.0/bin/pnpm
    bun: 1.0.0 - ~/.bun/bin/bun
  Browsers:
    Chrome: 136.0.7103.114
    Safari: 17.6
  npmPackages:
    @rspack/cli: catalog: => 1.3.8 
    @rspack/core: catalog: => 1.3.8 

Details

I'm struggling to set up nestjs in my local app.

I see a lot of issues that look like this:

I also saw a lot of issues that look like this:

Inspired by https://github.com/web-infra-dev/rspack/issues/2741

I created an rspack config that looks like this:

const { RunScriptWebpackPlugin } = require('run-script-webpack-plugin');
const { rspack } = require('@rspack/core');

/** @type {import('@rspack/cli').Configuration} */
const config = {
    context: __dirname,
    target: 'node',

    entry: {
        main: ['@rspack/core/hot/poll?100', './src/main.ts'],
    },
    resolve: {
        extensions: ['...', '.ts', '.tsx', '.jsx'],
    },
    module: {
        rules: [
            {
                test: /\.ts$/,
                use: {
                    loader: 'builtin:swc-loader',
                    options: {
                        jsc: {
                            parser: {
                                syntax: 'typescript',
                                decorators: true,
                            },
                            transform: {
                                legacyDecorator: true,
                                decoratorMetadata: true,
                            },
                        },
                    },
                },
            },
        ],
    },
    optimization: {
        minimize: false,
        minimizer: [
            new rspack.SwcJsMinimizerRspackPlugin({
                minimizerOptions: {
                    // We need to disable mangling and compression for class names and function names for Nest.js to work properly
                    // The execution context class returns a reference to the class/handler function, which is for example used for applying metadata using decorators
                    // https://docs.nestjs.com/fundamentals/execution-context#executioncontext-class
                    compress: {
                        keep_classnames: true,
                        keep_fnames: true,
                    },
                    mangle: {
                        keep_classnames: true,
                        keep_fnames: true,
                    },
                },
            }),
        ],
    },
    externalsType: 'commonjs',
    plugins: [
        !process.env.BUILD &&
            new RunScriptWebpackPlugin({
                name: 'main.js',
                autoRestart: false,
            }),
    ].filter(Boolean),
    devServer: {
        devMiddleware: {
            writeToDisk: true,
        },
    },
    externals: [
        function (obj, callback) {
            const resource = obj.request;
            const lazyImports = [
                '@nestjs/core',
                '@nestjs/microservices',
                '@nestjs/platform-express',
                'cache-manager',
                'class-validator',
                'class-transformer',
                // ADD THIS
                '@nestjs/microservices/microservices-module',
                '@nestjs/microservices/server',
                '@nestjs/websockets',
                'amqplib',
                'nats',
                'socket.io-adapter',
                'utf-8-validate',
                'bufferutil',
                'kerberos',
                '@mongodb-js/zstd',
                'snappy',
                '@aws-sdk/credential-providers',
                'mongodb-client-encryption',
                '@nestjs/websockets/socket-module',
                'bson-ext',
                'snappy/package.json',
                'aws4',
                'lua',
                'sharp',
                'amqp-connection-manager',
                'swc-loader',
                'node-gyp',
                'pg-native',
                'loader-utils',
                'fsevents',
                'kafkajs',
                'mqtt',
                '@swc/wasm',
                '@swc/core',
                '@swc/core-darwin-arm64',
                'swc+core-darwin-arm64',
                '@apollo/gateway',
                'apollo-server-fastify',
                'mock-aws-s3',
                '@mapbox+node-pre-gyp',
                'ts-morph',
            ];
            const requireImports = ['node-gyp', 'shard', 'sharp', 'fsevents'];
            if (requireImports.includes(resource)) {
                require.resolve(resource);
                callback(null, resource);
                return;
            }

            if (!lazyImports.includes(resource)) {
                return callback();
            }
            try {
                require.resolve(resource);
            } catch (err) {
                callback(null, resource);
            }
            callback();
        },
    ],
};
module.exports = config;

Reproduce link

https://github.com/MIreland/nestjs-rspack

Reproduce Steps

1. check out that repo
2. pnpm install
3. pnpm dev

[MIreland]

Also, how do I know what I should/shouldn't be putting in lazyImports in that config?

[kusham]

Hi, I’d like to work on this issue. Can I be assigned?

[mhadi512]

I was about to create a similar issue, having hard time setting up rspack with NestJS. I have a very minimal rspack.config and it's working. But I'm having an issue with Swagger docs, most DTOs appears empty object, seems like rspack are trimming reflect metadata for DTOs.