babel.config.js

'use strict'

module.exports = function (api) {
	//api.cache(true)
	api.cache.invalidate(() => process.env.NODE_ENV)

	const isProduction = api.env('production')

	return {
		babelrc: false,
		comments: !isProduction,
		plugins: isProduction
			? [
					[
						'@babel/plugin-transform-runtime',
						{
							absoluteRuntime: false,
							useESModules: true,
							version: '^7.14.0',
						},
					],
					// Stage 0
					//require('@babel/plugin-proposal-function-bind',

					// Stage 1
					'@babel/plugin-proposal-export-default-from',
					//'@babel/plugin-proposal-logical-assignment-operators',
					['@babel/plugin-proposal-optional-chaining', { loose: true }],
					//['@babel/plugin-proposal-pipeline-operator', { proposal: 'minimal' }],
					['@babel/plugin-proposal-nullish-coalescing-operator', { loose: true }],
					//'@babel/plugin-proposal-do-expressions',

					// Stage 2
					['@babel/plugin-proposal-decorators', { legacy: true }],
					//'@babel/plugin-proposal-function-sent',
					'@babel/plugin-proposal-export-namespace-from',
					//'@babel/plugin-proposal-numeric-separator',
					'@babel/plugin-proposal-throw-expressions',
					'@babel/plugin-proposal-unicode-property-regex',

					// Stage 3
					'@babel/plugin-syntax-dynamic-import',
					'@babel/plugin-syntax-import-meta',
					['@babel/plugin-proposal-class-properties', { loose: true }],
					'@babel/plugin-proposal-json-strings',

					[
						'babel-plugin-transform-imports',
						{
							reactstrap: {
								preventFullImport: true,
								transform: 'reactstrap/lib/${member}',
							},
						},
					],
					[
						'babel-plugin-transform-react-remove-prop-types',
						{
							additionalLibraries: ['react-immutable-proptypes'],
							removeImport: true,
						},
					],
					'babel-plugin-transform-react-pure-class-to-function',
					['@babel/plugin-transform-react-jsx', { runtime: 'automatic', importSource: 'preact', useBuiltIns: true, useSpread: true }], // @todo runtime: 'automatic',
					'babel-plugin-optimize-react',
					'babel-plugin-react-local',
					'babel-plugin-optimize-clsx',
					//'@babel/plugin-transform-react-constant-elements', // see https://github.com/facebookincubator/create-react-app/issues/553#issuecomment-359196326
					//['babel-plugin-transform-hoist-nested-functions', { methods: true }], // see ^^^
					//'babel-plugin-closure-elimination', // @TODO: Benchmark w/ & w/o, see ^^^ // broken collections portal navigation 21/11/2020

					// 'module:fast-async', - enabled from Chrome 55
					'babel-plugin-annotate-pure-calls',
					'./pure-plugin.js',
					['@babel/plugin-transform-strict-mode', { strict: true }],
					'babel-plugin-loop-optimizer',
					// 'emotion/babel'
			  ]
			: [
					// Stage 0
					//'@babel/plugin-proposal-function-bind',

					// Stage 1
					'@babel/plugin-proposal-export-default-from',
					//'@babel/plugin-proposal-logical-assignment-operators',
					['@babel/plugin-proposal-optional-chaining', { loose: true }],
					//['@babel/plugin-proposal-pipeline-operator', { proposal: 'minimal' }],
					['@babel/plugin-proposal-nullish-coalescing-operator', { loose: true }],
					//'@babel/plugin-proposal-do-expressions',

					// Stage 2
					['@babel/plugin-proposal-decorators', { legacy: true }],
					//'@babel/plugin-proposal-function-sent',
					'@babel/plugin-proposal-export-namespace-from',
					//'@babel/plugin-proposal-numeric-separator',
					'@babel/plugin-proposal-throw-expressions',
					'@babel/plugin-proposal-unicode-property-regex',

					// Stage 3
					'@babel/plugin-syntax-dynamic-import',
					'@babel/plugin-syntax-import-meta',
					['@babel/plugin-proposal-class-properties', { loose: true }],
					'@babel/plugin-proposal-json-strings',

					['@babel/plugin-transform-react-jsx', { pragma: 'h', pragmaFrag: 'Fragment', useBuiltIns: true }],
					// '@babel/plugin-transform-react-jsx-source', not useful for preact 06/04/2020
					'babel-plugin-transform-console-log-variable-names',
					'babel-plugin-console-groupify',
					['@babel/plugin-transform-strict-mode', { strict: true }],
					// 'emotion/babel'
					// 'runtyper'
			  ],
		presets: [
			[
				'@babel/preset-env',
				{
					bugfixes: true,
					exclude: ['transform-typeof-symbol'],
					loose: true,
					modules: 'auto',
					shippedProposals: true,
					targets: isProduction
						? undefined // -> reads .browserlistrc
						: {
								browsers: 'unreleased Chrome versions',
						  },
					useBuiltIns: false,
				},
				//'babel-preset-minify',
			],
		],
	}
}