Call require.default in dynamic import rewriter. (#356)

The require import we construct gets wrapped in the Babel helper
_interopRequireWildcard, which redefines require from a function to a
module object (with the original object at .default).

CHANGELOG.md

@@ -7,7 +7,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 <!-- ## Unreleased -->
 <!-- Add new, unreleased changes here. -->
-* Fix bug with node module resolution where specifiers in dynamic import() we're rewritten
+* Fix bug with node module resolution where specifiers in dynamic import() were rewritten.
+* Fix bug with dynamic import rewriting where imported require function could not be called.
 
 ## [3.0.0-pre.8] - 2018-04-04
 * Fix bug where not all percent-encoded characters in URIs would be decoded (in particular, `%40` -> `@` which is important for scoped NPM packages).

src/babel-plugin-dynamic-import-amd.ts

@@ -66,8 +66,12 @@ export const dynamicImportAmd = {
       // Transform the dynamic import callsites
       for (const importPath of dynamicImports) {
         const specifier = importPath.node.arguments[0];
+        // Call as `require.default` because the AMD transformer that we assume
+        // is running next will rewrite `require` from a function to a module
+        // object with the function at `default`.
         importPath.replaceWith(ast`(
-          new Promise((res, rej) => ${requireId}([${specifier}], res, rej))
+          new Promise((res, rej) => ${requireId}.default([${
+            specifier}], res, rej))
         )`);
       }
     },

src/test/babel-plugin-dynamic-import-amd_test.ts

@@ -21,15 +21,14 @@ import {dynamicImportAmd} from '../babel-plugin-dynamic-import-amd';
 const babelTransformModulesAmd = require('@babel/plugin-transform-modules-amd');
 
 suite('babel-plugin-transform-modules-amd', () => {
-
   test('transforms import()', () => {
     const input = stripIndent(`
       const foo = import('./foo.js');
     `);
 
     const expected = stripIndent(`
       import * as _require from 'require';
-      const foo = new Promise((res, rej) => _require(['./foo.js'], res, rej));
+      const foo = new Promise((res, rej) => _require.default(['./foo.js'], res, rej));
     `);
     const result =
         babelCore.transform(input, {plugins: [dynamicImportAmd]}).code;
@@ -49,10 +48,10 @@ suite('babel-plugin-transform-modules-amd', () => {
     const expected = stripIndent(`
       import * as _require3 from 'require';
       let _require = true;
-      const foo = new Promise((res, rej) => _require3(['./foo.js'], res, rej));
+      const foo = new Promise((res, rej) => _require3.default(['./foo.js'], res, rej));
       {
         let _require2 = true;
-        new Promise((res, rej) => _require3(['./bar.js'], res, rej));
+        new Promise((res, rej) => _require3.default(['./bar.js'], res, rej));
       }
     `);
     const result =
@@ -74,7 +73,6 @@ suite('babel-plugin-transform-modules-amd', () => {
         result, `define(["require", "./bar.js"], function (_require, _bar) {`);
     assert.include(
         result,
-        `const foo = new Promise((res, rej) => _require(['./foo.js'], res, rej));`);
+        `const foo = new Promise((res, rej) => _require.default(['./foo.js'], res, rej));`);
   });
-
 });

src/test/js-transform_test.ts

@@ -314,6 +314,6 @@ suite('jsTransform', () => {
         `define(["exports", "require", "dep1"], function (_exports, _require, _dep) {`);
     assert.include(
         result,
-        `console.log(new Promise((res, rej) => _require(['./bar.js'], res, rej)));`);
+        `console.log(new Promise((res, rej) => _require.default(['./bar.js'], res, rej)));`);
   });
 });