Merge pull request #365 from typed-ember/class-field-ordering

[v2]  Ensure consistency with `tsc` re: class property initialization order

Author: dfreeman

tests/unit/build-test.ts

@@ -27,4 +27,16 @@ module('Unit | Build', function() {
     assert.ok(fromTs);
     assert.equal(fromTs, 'From test-support');
   });
+
+  test('property initialization occurs in the right order', function(assert) {
+    class TestClass {
+      // we shouldn't encourage folks to write code like this, but tsc ensures
+      // that constructor param fields are set before field initializers run
+      field = this.constructorParam;
+      constructor(private constructorParam: string) {}
+    }
+
+    let instance = new TestClass('hello');
+    assert.equal(instance.field, 'hello');
+  });
 });

ts/addon.ts

@@ -67,7 +67,6 @@ export default addon({
     // preprocessor registry, so we need to beat it to the punch.
     this._registerBabelExtension();
 
-    this._addPluginIfMissing('@babel/plugin-transform-typescript');
     this._addPluginIfMissing(
       '@babel/plugin-proposal-class-properties',
       { loose: true },
@@ -76,6 +75,10 @@ export default addon({
         after: ['@babel/plugin-proposal-decorators'],
       }
     );
+
+    // Needs to come after the class properties plugin (see tests/unit/build-test.ts -
+    // "property initialization occurs in the right order")
+    this._addPluginIfMissing('@babel/plugin-transform-typescript');
   },
 
   shouldIncludeChildAddon(addon) {