support webpack@5

Issue description

…

Technical info

• Webpack Bundle Analyzer version: latest
• Webpack version: next (5)
• Node.js version: 10.13.0
• npm/yarn version: npm 6.13.4
• OS: Linux Ubuntu

Debug info

Support webpack@5 (will be great have CI and fix test to ensure all works as expected)

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Additional comment by @valscion in https://github.com/webpack-contrib/webpack-bundle-analyzer/issues/327#issuecomment-729614325:

This one for example has been open almost a year, and the webpack v5 stable release was over a month ago.

Do note that webpack-bundle-analyzer does work with webpack version 5. There is some combination of options which breaks, but not all of webpack 5.

We even test that this package works with webpack v5: https://github.com/webpack-contrib/webpack-bundle-analyzer/tree/master/test/webpack-versions/5.4.0

So this is only an edge case that is broken, not the entire support for webpack 5.

[Linksku]

After upgrading to webpack@^5.0.0-beta.22, webpack-bundle-analyzer just shows a single main.js, while other packages such as webpack-visualizer are able to display my files correctly. The content of stats.json looks normal.

Interestingly, after I added back Webpack 4 with yarn add webpack4@npm:webpack@latest, using webpack4 to generate stats.json produces the same issue of a single main.js. If I completely remove Webpack 5, then webpack-bundle-analyzer works again.

Any ideas on how to build using Webpack 5 normally, but use Webpack 4 just for webpack-bundle-analyzer?

[sokra]

webpack has a different output AST so the parser need to be adjusted. It also gets a little bit more challenging as more variations are possible:

/******/ (() => { // webpackBootstrap
/******/ 	var __webpack_modules__ = ([
MODULES HERE
/******/ 	]);

/******/ (() => { // webpackBootstrap
/******/ 	"use strict";
/******/ 	var __webpack_modules__ = ([
MODULES HERE
/******/ 	]);

(() => {
	var e = [
MODULES HERE
        ], r = {};
	function t(o) {
		if (r[o]) return r[o].exports;
		var n = (r[o] = { exports: {} });
		return e[o](n, n.exports, t), n.exports;
	}

Arrow functions may also be normal functions when output.ecmaVersion: 5.

Arrays might be objects too, as with webpack 4.

There might also be one entry module inlined into the runtime code, which is very difficult to identify in production mode.