Parcel: Code duplicated when using Dynamic Imports

[nick-woodward]

This a 🐛 bug report.

Based on How it Works and issue #37 it seems as though this is a bug.

When splitting your code, if a common module is included in both the parent and child it is duplicated rather then shared.

🎛 Configuration (.babelrc, package.json, cli command)

{
  "your": { "config": "here" }
}

🤔 Expected Behavior

Common code is shared.

😯 Current Behavior

Common code is duplicated.

🔦 Context

Increases the size of the bundle, could potentially cause problems in cases where something can't be defined multiple times. (i.e. web components)

💻 Code Sample

Just open up the console when you look at the demo.
You'll see that common.js is logged multiple times.

https://parcel-bundler-dynamic-dedupe.glitch.me _Edit_

🌍 Your Environment

| Software | Version(s) |
| ---------------- | ---------- |
| Parcel | 1.7.0
| Node | v9.11.1
| Yarn | 1.5.1
| Operating System | MacOS High Sierra 10.13.3

[PatrickSachs]

Are there any updates/fixes for this?

I just switched over to Parcel from Webpack only to discover that all my Vendor code is also included in all bundles.

// Edit - Screenshot of my main & admin bundle: https://prnt.sc/jai2rc

[devongovett]

Currently common code is hoisted to the parent bundle, but that will change in Parcel 2. We will be creating a separate bundle that loads in parallel with the shared code. See #885.