(feat): Add build command by wrapping rollup

[JayaKrishnaNamburu]

This PR aims to introduce the build command. Which will work in 2 modes. Basically the command wraps the rollup Node API with some defaults to run in simple mode. Where, we define some standard defaults and works with some projects out of the box.

jspm build --entry app.js --output build/

Then there is an another mode, where users can extend the behaviour with custom rollup setups. And the wrapper loads the config from the URL and starts the build.

jspm build --build-config build.mjs

is a simple rollup file. Which can have any defaults in it. Example

// build.mjs
import { defineConfig } from "rollup";
import banner from "rollup-plugin-banner";
import { babel } from "@rollup/plugin-babel";
import { nodeResolve } from "@rollup/plugin-node-resolve";

export default defineConfig({
  input: "./app.js",
  plugins: [
    nodeResolve(),
    babel({
      presets: ["@babel/preset-react"],
    }),
    banner.default("Running rolup with a wrapper around with jspm cli"),
  ],
  output: {
    file: "./build.js",
  },
});

Which generates a output of

// Running rolup with a wrapper around with jspm cli
import react from 'react';

console.log('This is from utils file');

console.log(react);
const App = () => {
  return /*#__PURE__*/React.createElement("div", null, "Hello World");
};

export { App };

The importmap.json processing is not handled yet. But once done, it can bundle react from jspm CDN and include in the build.

[JayaKrishnaNamburu]

Made some resolution changes with the rollup-plugin now. It can download the deps and bundle them too.
The command

jspm build --build-config build-config.mjs

downloads all the dependencies that are defined in the importmap.json and bundles them along.

[JayaKrishnaNamburu]

Crazy how this wraps the whole vite-plugin-jspm functionality 😄

[guybedford]

Excellent work, very exciting to see this one. Can you add some tests? Let me know if you need help getting them going.

[guybedford]

Also documentation should be added in https://github.com/jspm/jspm-cli/tree/main/docs, which would then get added to the site.

[JayaKrishnaNamburu]

Thanks for the review @guybedford, good to see that the PR was in the right direction 😄. Will make the necessary changes, and see how we can integrate this with other commands. Like we have traceInstall available with jspm installl that updates .html files.

But if users are bundling the deps too. We don't need to add importmap anymore. So, just trying to list use-cases like those. And see how we can streamline the workflows and connect these commands more together 👍

[JayaKrishnaNamburu]

@guybedford made the final changes, and added the documentation for the same. Please check if need any changes/we can merge and release it.

[guybedford]

Thanks for working on the feedback here. I've left another couple of change requests. With those I think we could then approve and land and release. Ping me on discord if you want to discuss further at all.

[JayaKrishnaNamburu]

Done with the directory changes 👍

[guybedford]

Thanks, looks good down to the externals handling versus resolution errors.

[JayaKrishnaNamburu]

Should i release 3.1.0 with this change ?

[guybedford]

Yes please!