[V2] How to speed up parcel in development?

❔ Question

import { CssBaseline, Button } from "@material-ui/core";
import React from "react";
import ReactDOM from "react-dom";

ReactDOM.render(
  <div>
    <CssBaseline />
    <Button>Hi2</Button>
  </div>,
  document.getElementById("root")
);

The above code took 3~5 seconds on rebuild when I add new character inside Button component. I noticed the bundler optimizing index.html on every rebuild. Is it the expected behavior? How to speed thing up?

I use parcel serve index.html command to bundle my react application.

🔦 Context

"parcel": "^2.0.0-alpha.3.2"
"react": "16.12.0",
"react-dom": "16.12.0",
"@material-ui/core": "4.7.0",

💻 Code Sample

🌍 Your Environment

Software	Version(s)
Parcel	2.0.0-alpha 3.2
Node	10.17.0
npm/Yarn	Yarn 1.19.1
Operating System	MacOS Catalina 10.15.2 Beta (19C32e)

[witoszekdev]

Okay, so I’ve done more testing and indeed this doesn’t solve the issue 😕

This is rebuild in V2:

And here is from V1:

And for good measure, this is the same app build using Create-React-App (sorry for the video form, but CRA doesn’t show the rebuild time as Parcel does). It builds basically in milliseconds 😬.

Note: I have recently reinstalled macOS from scratch…

Here is the codebase that I’ve run those test on: https://github.com/taniotanio7/parcel-performance-test

[xiaoyu-tamu]

Looks like fixed in #4417