Convert package to ESM w/ fallbacks

.babelrc

@@ -1,9 +1,13 @@
 {
 	"presets": [
-		"@babel/preset-env"
+		["@babel/preset-env", {
+			"targets": [
+				"defaults",
+				"maintained node versions"
+			]
+		}]
 	],
 	"plugins": [
-		"@babel/plugin-transform-class-properties",
 		"@babel/plugin-transform-runtime"
 	]
 }

.eslintignore

@@ -1,4 +1,2 @@
 /coverage
 /dist
-/lib
-/types

.eslintrc.json

@@ -1,13 +1,11 @@
 {
 	"extends": [
 		"eslint:recommended",
-		"plugin:compat/recommended",
-		"plugin:jsdoc/recommended",
 		"ultraq"
 	],
-	"parser": "@babel/eslint-parser",
 	"parserOptions": {
-		"ecmaVersion": 2020
+		"ecmaVersion": 2022,
+		"sourceType": "module"
 	},
 	"env": {
 		"browser": true,

.gitignore

@@ -1,6 +1,4 @@
 /.idea
 /coverage
 /dist
-/lib
 /node_modules
-/types

README.md

@@ -34,11 +34,11 @@ npm install @ultraq/icu-message-formatter
 ### As a script for the browser via the unpkg CDN:
 
 An IIFE version of this library is available at:
-https://unpkg.com/@ultraq/icu-message-formatter/dist/icu-message-formatter.min.js
+https://unpkg.com/@ultraq/icu-message-formatter/dist/icu-message-formatter.browser.min.js
 In this form, this module will then be present in the global scope as `IcuMessageFormatter`.
 
 An ESM version of this library is available at:
-https://unpkg.com/@ultraq/icu-message-formatter/dist/icu-message-formatter.es.min.js
+https://unpkg.com/@ultraq/icu-message-formatter/dist/icu-message-formatter.browser.es.min.js
 That URL can be used directly in ESM scripts made for the browser, and otherwise
 works like the NPM package.
 

jest.config.js

@@ -1,7 +1,5 @@
-/* eslint-env node */
-'use strict'; // eslint-disable-line
-
-module.exports = {
+/** @type {import('jest').Config} */
+const config = {
 	collectCoverage: true,
 	collectCoverageFrom: [
 		'source/**/*.js'
@@ -23,3 +21,5 @@ module.exports = {
 		'./jest.setup.js'
 	]
 };
+
+export default config;

jest.setup.js

@@ -1,8 +1,5 @@
-/* eslint-env node */
-'use strict'; // eslint-disable-line
-
 // Node has an Intl object, but doesn't ship with any locale information, so we
 // need to patch parts of it to work as it does in the browser.
-require('@formatjs/intl-locale/polyfill');
-require('@formatjs/intl-numberformat/polyfill');
-require('@formatjs/intl-numberformat/locale-data/en-NZ');
+import '@formatjs/intl-locale/polyfill';
+import '@formatjs/intl-numberformat/polyfill';
+import '@formatjs/intl-numberformat/locale-data/en-NZ';