Document altering entry point (allowing ember addon and "normal" package usage).

[rwjblue]

In ember-cli (for a very very long time) it has been possible to have ember-cli use a different main entry point for the addon than what a normal require('my-package-name') would return.

The way to do this is to add an "ember-addon": { "main": "some-other-file.js" } to your package.json. Normal require invocation will look at the main entry point, and ember-cli will look at some-other-file.js.

One nice benefit of this is that if you make main be addon/index.js and ember-addon.main be index.js, "normal" node_module resolution rules apply for things in addon/index.js. This means that things like eslint-plugin-import and TypeScript can actual see and validate an import from the addon name (though not with nested paths).

For example, typescript (and eslint-plugin-import) would see that this is valid:

import Component from 'sparkles-component';

export default class extends Component {}

See rwjblue/sparkles-component#23 as an example.

[xg-wang]

I think this should be a RFC and built into default addon blueprint, rather than teaching addon authors.
^^ For the making typescript happy part, this needs to be documented

[rwjblue]

Sure, seems totally fine to me.