What is the difference between compiling swc and bundling spack and when should you use one vs other?

[samesfahani-tuplehealth]

Sorry if this is an obvious question, but I was curious to know what the difference between building an entire directory with swc ./src -d dist versus the following setup:

spack.config.js

const { config } = require('@swc/core/spack');

module.exports = config({
  entry: {
    example: __dirname + '/src/index.ts',
  },
  output: {
    path: __dirname + '/dist',
  },
  options: {
    swcrc: true,
  },
  target: 'node',
  module: {},
});

My best observations are that:

1. swc ./src -d dist is going to compile the entire codebase in the same structure as they currently are
2. spack is going to look at src/index.ts, traverse through the full dependency graph, concatenate everything into one output (as opposed to multiple files). As a result you have one file that is tree shaken.

Is my understanding correct? A few questions:

1. When should you use one approach versus the other?
2. What if your entry file doesn't call a function but simply defines a set of functions? My use case here is that I am defining an AWS Lambda function that may import other dependencies, but in that entry point, no function will be called. This is unlike a server start file that would call a bootstrap() function. As a result, would my compiled output just be empty? Or will it be okay as long as I have something exported?