woocommerce/plugins/woocommerce-blocks/tests/js/jestPreprocess.js

const babelOptions = {
	presets: [ '@babel/preset-typescript', '@wordpress/babel-preset-default' ],
	plugins: [
		'explicit-exports-references',
		'@babel/plugin-proposal-class-properties',
	],
};

module.exports = require( 'babel-jest' ).default.createTransformer(
	babelOptions
);