Explain purpose for separate builds in readme about typescript-starter

[bitjson]

Hey @panshul007 – good question! Thanks for opening the issue.

tsconfig.module.json is actually an entirely separate build. If you look at the build script, we actually compile your project twice. I should probably add this to the readme. (thanks!)

Here's a draft explanation, please let me know if it's clear enough:

Multiple builds (main and module)

The src of typescript-starter is compiled into two separate builds, the main and module build. The main build is configured to use the CommonJS module system, while the module build uses the new ES6 module system.

Because Node.js does not yet support the ES6 module system, Node.js projects which depend on typescript-starter will follow the main field in package.json. Tools which support the new system (like Rollup) will follow the module field, giving them the ability to tree shake typescript-starter.

Note: by default, the main build is the only one exercised by the tests. While both builds are nearly identical, there are real differences in how the two module systems work. For most libraries, this won't be an issue, but for libraries with functionality that varies based on the module system used (generally a bad idea), additional testing is required.

[pgbytes]

Thanks, the explains a lot.