Summary

Improve the rendering of ExternalModule.

Before:

import * as __WEBPACK_EXTERNALS_foo__ from 'foo'

__WEBPACK_EXTERNALS_foo__.value

This PR:

import { value } from 'foo'

value

Design detail

Add a new concatenation hook named concatenation_info, this hook is used to let module prepare some data in the correct topological order, for example, moduleA, moduleB can use this hook to add their globally used names.

ExternalModule has global names because they will insert some import statements through InitFragment.

// a.js
import { a } from 'foo';
// b.js
import { a } from 'bar';

Tap this hook, and insert the a to the globally used names, so we can deconflict the conflict symbol name.

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).