Calypso Build: babel-plugin-optimize-i18n misses some spots

[mirka]

Overview

The i18n unmangling plugin added in #49341 seems to not be working in certain places.

While it works in most cases, it can still output functions like (0, l.__)("my string", "my-domain").

Context

I first encountered this issue when trying to integrate the update into P2 Blocks (2070-gh-Automattic/p2), where for some reason it fails in a lot of places.

I was able to observe it happening here in this repo as well:

1. Build the ETK editor-site-launch module.

   $ cd apps/editing-toolkit
   $ yarn build:editor-site-launch

2. Look at the dist files for focused-launch.js and gutenboarding-launch.js, and search for the string __)(. You should find a mangled i18n call: (0,r.__)("Site Title","full-site-editing").

I couldn't determine what the exact cause was, but I'm wondering if it is a Babel preset/plugin order issue. Because at least for the code in P2 Blocks, some of the instances are fixed if I invert the preset order here:

wp-calypso/packages/calypso-build/webpack.config.js

Lines 71 to 73 in 80da0b7

	presets = [
	path.join( __dirname, 'babel', 'default' ),
	env.WP && path.join( __dirname, 'babel', 'wordpress-element' ),

• yarn version: 1.22.10

cc: @jsnajdr