feat: support class properties

Author: buschtoens

src/index.js

@@ -30,6 +30,10 @@ module.exports = {
         loader: 'babel-loader-8',
         options: {
           plugins: [
+            // Transpile class properties
+            // @see https://github.com/typed-ember/ember-cli-typescript/blob/b2e75abc98beefe635b6cfd8808c887813acb44e/ts/addon.ts#L99
+            require.resolve('@babel/plugin-proposal-class-properties'),
+
             // Transpile new syntax, which is apparently not yet handled by
             // `@babel/preset-env`.
             // @see https://github.com/typed-ember/ember-cli-typescript/blob/b2e75abc98beefe635b6cfd8808c887813acb44e/ts/addon.ts#L89-L94

src/package.json

@@ -16,6 +16,7 @@
     "lint:js": "eslint --ext ts,js ."
   },
   "dependencies": {
+    "@babel/plugin-proposal-class-properties": "^7.8.3",
     "@babel/plugin-proposal-nullish-coalescing-operator": "^7.8.3",
     "@babel/plugin-proposal-optional-chaining": "^7.8.3",
     "@babel/preset-env": "^7.8.4",

tests/ts-module-b/some/nested-file.ts

@@ -1,3 +1,7 @@
+export class Foo {
+  bar = false;
+}
+
 const foo = { bar: { baz: undefined } };
 
 export const works = foo.bar?.baz ?? (() => true);