Merge pull request #677 from dfreeman/ts-declaration-merging

Support TypeScript merging of export default declarations in template colocation

Author: Robert Jackson

lib/colocated-babel-plugin.js

@@ -22,7 +22,17 @@ module.exports = function (babel) {
       },
 
       ExportDefaultDeclaration(path, state) {
-        if (state.colocatedTemplateFound !== true || state.setComponentTemplateInjected === true) {
+        let defaultExportDeclarationPath = path.get('declaration');
+        let defaultExportIsExpressionOrClass =
+          defaultExportDeclarationPath.isClass() ||
+          defaultExportDeclarationPath.isExpression() ||
+          defaultExportDeclarationPath.isFunction();
+
+        if (
+          state.colocatedTemplateFound !== true ||
+          state.setComponentTemplateInjected === true ||
+          !defaultExportIsExpressionOrClass
+        ) {
           return;
         }
 

node-tests/colocated-babel-plugin-test.js

@@ -5,6 +5,7 @@ const babel = require('@babel/core');
 const { stripIndent } = require('common-tags');
 const ColocatedBabelPlugin = require('../lib/colocated-babel-plugin');
 const DecoratorsPlugin = [require.resolve('@babel/plugin-proposal-decorators'), { legacy: true }];
+const TypeScriptPlugin = [require.resolve('@babel/plugin-transform-typescript')];
 const ClassPropertiesPlugin = [
   require.resolve('@babel/plugin-proposal-class-properties'),
   { loose: true },
@@ -68,6 +69,31 @@ describe('ColocatedBabelPlugin', function () {
     );
   });
 
+  it('can be used with TypeScript merged declarations', function () {
+    let { code } = babel.transformSync(
+      stripIndent`
+        import Component from 'somewhere';
+        const __COLOCATED_TEMPLATE__ = 'ok';
+        type MyArgs = { required: string; optional?: number };
+
+        export default interface MyComponent extends MyArgs {}
+        export default class MyComponent extends Component {}
+      `,
+      { plugins: [ColocatedBabelPlugin, TypeScriptPlugin] }
+    );
+
+    assert.strictEqual(
+      code,
+      stripIndent`
+        import Component from 'somewhere';
+        const __COLOCATED_TEMPLATE__ = 'ok';
+        export default class MyComponent extends Component {}
+
+        Ember._setComponentTemplate(__COLOCATED_TEMPLATE__, MyComponent);
+      `
+    );
+  });
+
   it('sets the template for non-class default exports', function () {
     let { code } = babel.transformSync(
       stripIndent`