fix(chore): fix main file location, ensure compatibility with nodejs

[3cp]

The current setup uses implicit default main file index.js which uses es6 native module import syntax, and directly loads from source file (lib folder) which uses native module import syntax too.

The whole setup bypasses dist file prepared by rollup.

The reason that this setup still works in webpack, is webpack supports es6 native module import syntax. We don't have the luck if we use the main file in nodejs or browser environments directly (both currently do not support import syntax by default).

[nikku]

What is your setup / which setups would you like to support?

[3cp]

The linked issue above uses aureli-cli which uses a requirejs based build, it supports normal commonjs/umd/amd code which is shipped by most npm packages.

The current setup stops nodejs with a simple var BpmnJS = require('bpmn-js');.
But var BpmnJS = require('bpmn-js/dist/bpmn-viewer.production.min'); works fine after properly preparing jsdom.

[nikku]

I guess aurelia is using browserify to consume libraries and bundle things for the browser.

Did you consider adding the respective babelify transform to translate ES module import / export declarations to cjs?

[nikku]

The alternative is to use the workaround you provide.

[3cp]

Not browserify, aurelia uses amodra-trace currently which translate cjs into amd module.
It does babel on source code but skipped all npm modules as it assume all npm modules provided code understandable by nodejs.

I think it's a common practice to ship npm package in a format which is understandable by nodejs. After all, npm package is designed to be consumed by nodejs.

This PR would not affect webpack, just reduce its effert in dealing with import and bundling multiple files which is already done by rollup.

[3cp]

I understand, this is not a big issue for using bpmn in aurelia. After all, it's your call whether to make it smoother to nodejs env and other bundlering tool other than webpack.

[nikku]

After all, it's your call whether to make it smoother to nodejs env and other bundlering tool other than webpack.

We came from CommonJS and switched to ES modules for reasons such as smaller bundle sizes / tree shaking. My guess is that eventually, all decent bundlers and NodeJS will understand ES modules, as it is the new standard for JavaScript modules.

Before we reach this point, people that are forced into AMD / cjs environments with no ability to control the actual transpilation should resort to the workaround you mentioned:

var BpmnJS = require('bpmn-js/dist/bpmn-viewer.production.min') works fine after properly preparing jsdom.

[3cp]

Thx for the reasoning. Appreciated.