2.0.0 Source map build performance

[cliedeman]

Is this a bug report?

No

Environment

Environment:
OS: macOS High Sierra 10.13.6
Node: 8.12.0
Yarn: 1.9.4
npm: 6.4.1
Watchman: 4.9.0
Xcode: Xcode 9.4.1 Build version 9F2000
Android Studio: 3.0 AI-171.4443003

Packages: (wanted => installed)
react: ^16.5.2 => 16.5.2
react-dom: ^16.5.2 => 16.5.2
react-scripts: ^2.0.0 => 2.0.0

Steps to Reproduce

1. npx create-react-app test-app # must use react-script@2.0.0
2. yarn add britecharts-react
3. Render any graph in App.js
4. yarn build

Expected Behavior

yarn build runs in a reasonable time

Actual Behavior

Build time jumps to 90 seconds, from 15 seconds

Reproducible Demo

Example Project

react-scripts@2.0.0 14.03s. (without britecharts)
react-scripts@2.0.0 89.04s (with britecharts)

react-scripts@1.1.5: 28.73s. (with britecharts)
react-scripts@1.1.5 : 6.93s. (without britecharts)

[Timer]

Why is their bundled build so much smaller than the esm? What kind of minification are they performing?

[Timer]

Wait, where are you getting those build sizes from?

Creating an optimized production build...
Compiled successfully.

File sizes after gzip:

  493.84 KB  build/static/js/1.c4b7e5c3.chunk.js
  448 B      build/static/js/main.decdb3c3.chunk.js
  231 B      build/static/css/main.f67ca539.chunk.css

[Timer]

Hm, removing the map didn't make the build any faster for me. Can you give a better repro?

[Timer]

x-ref: #5103 (comment)

[cliedeman]

Sorry about that.... I created a more robust setup script with docker and got exactly the same times across the board.
I have no idea where I got those bundles sizes from and can't reproduce them now.

I have removed that section from the issue to focus on the build time change

[cliedeman]

Updated the example project and split into 4 scenarios and added a single script so its easier to run.

Env	Cold (seconds)	Warm (seconds)
CRA 1.1.5 with britecharts	28.14	27.32
CRA 1.1.5 without britecharts	7.67	6.87
CRA 2.0.5 with britecharts	122.26	16.63
CRA 2.0.5 without britecharts	9.71	6.79